$98+ Cheap flights from Ontario (ONT) to Chicago (CHI)
This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 9/9. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — CHI
Aug 8 — Aug 151
Round-trip
1 adult, Economy
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Find cheap flights from Ontario to Chicago with Cheapflights
1. Tell us where you want to go
Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”2. Select your favorite providers
We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.3. Compare prices and book
Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.Cheapflights Tip: The best prices from Ontario to Chicago are usually found in January or October, booked 85 days in advance, depart on a Wednesday or Saturday and return on a Wednesday
Cheap flight deals from Ontario to Chicago
Cheapest
Best
Last-minute
One-way
Cheapest flights from Ontario to ChicagoExplore the most affordable flight options available from Ontario to Chicago. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 9, 2026.
Explore the most affordable flight options available from Ontario to Chicago. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 9, 2026.
This Kiwi.com deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/88:17 am
ONT
- MDW
1 stop7h 09m
Frontier
Tue 8/115:46 pm
MDW
- ONT
1 stop16h 55m
Frontier
Deal found 7/8![Frontier logo]()
$280
This Frontier deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/319:32 am
ONT
- ORD
1 stop13h 17m
Frontier
Tue 8/117:29 am
ORD
- ONT
1 stop9h 45m
Frontier
Deal found 7/8![Frontier logo]()
$280
This Southwest deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/1111:55 pm
ONT
- MDW
Nonstop3h 50m
Southwest
Fri 9/182:00 pm
MDW
- ONT
Nonstop4h 10m
Southwest
Deal found 7/8![Southwest logo]()
$281
This Frontier deal was found by Cheapflights users on 7/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/104:09 pm
ONT
- ORD
1 stop11h 28m
Frontier
Tue 8/182:41 pm
ORD
- ONT
1 stop11h 09m
Frontier
Deal found 7/5![Frontier logo]()
$281
This Southwest deal was found by Cheapflights users on 7/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/96:40 am
ONT
- MDW
2 stops8h 30m
Southwest
Thu 9/105:00 pm
MDW
- ONT
2 stops7h 10m
Southwest
Deal found 7/9![Southwest logo]()
$282
This Kiwi.com deal was found by Cheapflights users on 7/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/64:09 pm
ONT
- ORD
1 stop11h 28m
Frontier
Mon 8/107:29 am
ORD
- ONT
1 stop26h 34m
Frontier
Deal found 7/9![Frontier logo]()
$282
This Booking.com deal was found by Cheapflights users on 7/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/42:35 pm
ONT
- ORD
1 stop17h 26m
Frontier
Wed 11/112:46 pm
ORD
- ONT
1 stop25h 51m
Frontier
Deal found 7/6![Frontier logo]()
$283
This Southwest deal was found by Cheapflights users on 7/7. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/2011:55 pm
ONT
- MDW
Nonstop3h 45m
Southwest
Sat 10/2410:30 am
MDW
- ONT
2 stops9h 40m
Southwest
Deal found 7/7![Southwest logo]()
$284
This United Airlines deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/51:50 pm
ONT
- ORD
1 stop9h 09m
United Airlines
Wed 8/128:06 pm
ORD
- ONT
Nonstop4h 29m
United Airlines
Deal found 7/8![United Airlines logo]()
$284
This Southwest deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/266:40 am
ONT
- MDW
2 stops8h 30m
Southwest
Wed 9/910:30 am
MDW
- ONT
2 stops7h 35m
Southwest
Deal found 7/8![Southwest logo]()
$285
This Super.com deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/125:08 pm
ONT
- ORD
1 stop10h 29m
Frontier
Mon 8/179:57 pm
ORD
- ONT
1 stop14h 07m
Frontier
Deal found 7/8![Frontier logo]()
$285
This Delta deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/67:05 am
ONT
- MDW
2 stops9h 00m
Delta
Tue 10/2012:28 pm
MDW
- ONT
2 stops12h 15m
Delta
Deal found 7/8![Delta logo]()
$286
Best flights from Ontario to ChicagoDiscover carefully curated flight deals from Ontario to Chicago that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated July 9, 2026.
Discover carefully curated flight deals from Ontario to Chicago that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated July 9, 2026.
This Southwest deal was found by Cheapflights users on 7/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/2711:55 pm
ONT
- MDW
Nonstop3h 50m
Southwest
Thu 10/16:05 am
MDW
- ONT
1 stop5h 50m
Southwest
Deal found 7/9![Southwest logo]()
$345
This United Airlines deal was found by Cheapflights users on 7/7. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/17:00 am
ONT
- ORD
Nonstop4h 10m
United Airlines
Mon 10/58:20 pm
ORD
- ONT
Nonstop4h 29m
United Airlines
Deal found 7/7![United Airlines logo]()
$355
This Delta deal was found by Cheapflights users on 7/7. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/11:06 pm
ONT
- ORD
1 stop6h 27m
Delta
Thu 9/37:44 pm
ORD
- ONT
1 stop5h 50m
Delta
Deal found 7/7![Delta logo]()
$371
This Kiwi.com deal was found by Cheapflights users on 7/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/246:00 am
ONT
- RFD
2 stops24h 52m
Multiple Airlines
Sun 9/279:29 pm
RFD
- ONT
1 stop14h 52m
Multiple Airlines
Deal found 7/4![Multiple Airlines logo]()
$373
This Southwest deal was found by Cheapflights users on 7/7. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/58:20 am
ONT
- MDW
2 stops7h 25m
Southwest
Fri 10/911:55 am
MDW
- ONT
Nonstop4h 15m
Southwest
Deal found 7/7![Southwest logo]()
$346
This Delta deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/910:00 pm
ONT
- MDW
1 stop9h 59m
Delta
Wed 8/1212:46 pm
MDW
- ONT
2 stops12h 48m
Delta
Deal found 7/8![Delta logo]()
$376
This Southwest deal was found by Cheapflights users on 7/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/96:40 am
ONT
- MDW
2 stops8h 30m
Southwest
Sun 9/135:25 am
MDW
- ONT
1 stop6h 05m
Southwest
Deal found 7/9![Southwest logo]()
$360
This United Airlines deal was found by Cheapflights users on 7/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/67:00 am
ONT
- ORD
Nonstop4h 10m
United Airlines
Wed 9/98:30 pm
ORD
- ONT
Nonstop4h 29m
United Airlines
Deal found 7/4![United Airlines logo]()
$398
This Delta deal was found by Cheapflights users on 7/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/306:00 pm
ONT
- ORD
2 stops12h 30m
Delta
Sat 10/38:25 am
ORD
- ONT
2 stops10h 10m
Delta
Deal found 7/5![Delta logo]()
$382
This Southwest deal was found by Cheapflights users on 7/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/65:15 am
ONT
- MDW
2 stops7h 20m
Southwest
Thu 8/135:40 am
MDW
- ONT
1 stop5h 40m
Southwest
Deal found 7/9![Southwest logo]()
$360
This United Airlines deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/61:18 pm
ONT
- ORD
1 stop8h 01m
United Airlines
Wed 8/125:55 am
ORD
- ONT
1 stop8h 55m
United Airlines
Deal found 7/8![United Airlines logo]()
$413
This Southwest deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/912:40 pm
ONT
- MDW
1 stop8h 05m
Southwest
Wed 8/125:15 pm
MDW
- ONT
1 stop6h 50m
Southwest
Deal found 7/8![Southwest logo]()
$371
This Delta deal was found by Cheapflights users on 7/7. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/310:00 pm
ONT
- MDW
1 stop9h 59m
Delta
Fri 8/712:46 pm
MDW
- ONT
1 stop7h 44m
Delta
Deal found 7/7![Delta logo]()
$409
This Kiwi.com deal was found by Cheapflights users on 7/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/2711:16 am
ONT
- RFD
1 stop7h 23m
Multiple Airlines
Thu 10/19:03 pm
RFD
- ONT
1 stop15h 18m
Multiple Airlines
Deal found 7/9![Multiple Airlines logo]()
$545
This Delta deal was found by Cheapflights users on 7/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/226:00 pm
ONT
- MDW
2 stops13h 07m
Delta
Mon 9/286:05 am
MDW
- ONT
1 stop7h 02m
Delta
Deal found 7/9![Delta logo]()
$442
This United Airlines deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/107:00 am
ONT
- ORD
Nonstop4h 10m
United Airlines
Sun 9/138:30 pm
ORD
- ONT
Nonstop4h 29m
United Airlines
Deal found 7/8![United Airlines logo]()
$488
This Kiwi.com deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 7/233:40 pm
ONT
- RFD
2 stops26h 43m
Multiple Airlines
Sun 7/261:14 pm
RFD
- ONT
1 stop20h 49m
Multiple Airlines
Deal found 7/8![Multiple Airlines logo]()
$551
This Southwest deal was found by Cheapflights users on 7/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/2511:55 pm
ONT
- MDW
Nonstop3h 50m
Southwest
Mon 8/318:00 am
MDW
- ONT
2 stops9h 05m
Southwest
Deal found 7/4![Southwest logo]()
$442
This United Airlines deal was found by Cheapflights users on 7/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/247:00 am
ONT
- ORD
Nonstop4h 10m
United Airlines
Tue 9/298:20 pm
ORD
- ONT
Nonstop4h 29m
United Airlines
Deal found 7/4![United Airlines logo]()
$498
This Delta deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/910:00 pm
ONT
- ORD
2 stops13h 08m
Delta
Wed 8/121:59 pm
ORD
- ONT
2 stops11h 35m
Delta
Deal found 7/8![Delta logo]()
$457
This Southwest deal was found by Cheapflights users on 7/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/2511:55 pm
ONT
- MDW
Nonstop3h 50m
Southwest
Mon 9/282:00 pm
MDW
- ONT
Nonstop4h 10m
Southwest
Deal found 7/4![Southwest logo]()
$447
This United Airlines deal was found by Cheapflights users on 7/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/147:00 am
ONT
- ORD
Nonstop4h 10m
United Airlines
Sun 10/186:00 am
ORD
- ONT
1 stop8h 46m
United Airlines
Deal found 7/6![United Airlines logo]()
$508
This Delta deal was found by Cheapflights users on 7/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/116:00 pm
ONT
- ORD
2 stops12h 38m
Delta
Mon 9/145:10 pm
ORD
- ONT
2 stops8h 37m
Delta
Deal found 7/4![Delta logo]()
$475
This Southwest deal was found by Cheapflights users on 7/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/211:55 pm
ONT
- MDW
Nonstop3h 45m
Southwest
Sun 8/95:25 am
MDW
- ONT
1 stop6h 05m
Southwest
Deal found 7/5![Southwest logo]()
$457
This Delta deal was found by Cheapflights users on 7/7. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/510:00 pm
ONT
- ORD
2 stops10h 39m
Delta
Fri 10/911:19 am
ORD
- ONT
2 stops12h 42m
Delta
Deal found 7/7![Delta logo]()
$477
This United Airlines deal was found by Cheapflights users on 7/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/76:10 am
ONT
- ORD
Nonstop4h 15m
United Airlines
Sun 8/98:18 pm
ORD
- ONT
Nonstop4h 33m
United Airlines
Deal found 7/6![United Airlines logo]()
$545
Last-minute flights from Ontario to ChicagoDiscover last-minute flight deals from Ontario to Chicago. Data last updated July 9, 2026 and is based on user searches.
Discover last-minute flight deals from Ontario to Chicago. Data last updated July 9, 2026 and is based on user searches.
This Frontier deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/319:32 am
ONT
- ORD
1 stop13h 17m
Frontier
Tue 8/117:29 am
ORD
- ONT
1 stop9h 45m
Frontier
Deal found 7/8![Frontier logo]()
$280
This Super.com deal was found by Cheapflights users on 7/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/13:40 pm
ONT
- ORD
1 stop11h 57m
Frontier
Tue 8/49:34 pm
ORD
- ONT
1 stop13h 07m
Frontier
Deal found 7/6![Frontier logo]()
$286
This United Airlines deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/51:50 pm
ONT
- ORD
1 stop9h 09m
United Airlines
Wed 8/128:06 pm
ORD
- ONT
Nonstop4h 29m
United Airlines
Deal found 7/8![United Airlines logo]()
$284
This Kiwi.com deal was found by Cheapflights users on 7/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/64:09 pm
ONT
- ORD
1 stop11h 28m
Frontier
Mon 8/107:29 am
ORD
- ONT
1 stop26h 34m
Frontier
Deal found 7/9![Frontier logo]()
$282
This Booking.com deal was found by Cheapflights users on 7/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/610:49 am
ONT
- ORD
1 stop8h 03m
Frontier
Sat 8/89:57 pm
ORD
- ONT
1 stop14h 07m
Frontier
Deal found 7/9![Frontier logo]()
$288
This Kiwi.com deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/88:17 am
ONT
- MDW
1 stop7h 09m
Frontier
Tue 8/115:46 pm
MDW
- ONT
1 stop16h 55m
Frontier
Deal found 7/8![Frontier logo]()
$280
This Frontier deal was found by Cheapflights users on 7/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/104:09 pm
ONT
- ORD
1 stop11h 28m
Frontier
Tue 8/182:41 pm
ORD
- ONT
1 stop11h 09m
Frontier
Deal found 7/5![Frontier logo]()
$281
This Super.com deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/125:08 pm
ONT
- ORD
1 stop10h 29m
Frontier
Mon 8/179:57 pm
ORD
- ONT
1 stop14h 07m
Frontier
Deal found 7/8![Frontier logo]()
$285
This Southwest deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/121:50 pm
ONT
- MDW
1 stop7h 00m
Southwest
Sat 8/155:40 am
MDW
- ONT
1 stop7h 35m
Southwest
Deal found 7/8![Southwest logo]()
$288
This Delta deal was found by Cheapflights users on 7/7. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/196:00 am
ONT
- MDW
2 stops10h 01m
Delta
Tue 8/259:59 am
MDW
- ONT
2 stops8h 25m
Delta
Deal found 7/7![Delta logo]()
$286
This Southwest deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/266:40 am
ONT
- MDW
2 stops8h 30m
Southwest
Wed 9/910:30 am
MDW
- ONT
2 stops7h 35m
Southwest
Deal found 7/8![Southwest logo]()
$285
This Delta deal was found by Cheapflights users on 7/7. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/291:06 pm
ONT
- ORD
1 stop6h 27m
Delta
Wed 9/97:45 am
ORD
- ONT
1 stop6h 29m
Delta
Deal found 7/7![Delta logo]()
$287
One-way flights from Ontario to ChicagoSearch for one-way flight options from Ontario to Chicago. Find affordable one-way fares based on user searches. Data last updated July 9, 2026.
Search for one-way flight options from Ontario to Chicago. Find affordable one-way fares based on user searches. Data last updated July 9, 2026.
This Trip.com deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/99:49 pm
ONT
- ORD
1 stop12h 08m
Frontier
Deal found 7/8![Frontier logo]()
$98
This Southwest deal was found by Cheapflights users on 7/7. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/511:55 pm
ONT
- MDW
Nonstop3h 50m
Southwest
Deal found 7/7![Southwest logo]()
$99
This Kiwi.com deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/152:58 pm
ONT
- ORD
1 stop12h 44m
Frontier
Deal found 7/8![Frontier logo]()
$99
This Trip.com deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/142:58 pm
ONT
- ORD
1 stop12h 44m
Frontier
Deal found 7/8![Frontier logo]()
$103
This Kiwi.com deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/169:49 pm
ONT
- ORD
1 stop29h 53m
Frontier
Deal found 7/8![Frontier logo]()
$104
This Trip.com deal was found by Cheapflights users on 7/7. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/302:58 pm
ONT
- ORD
1 stop18h 59m
Frontier
Deal found 7/7![Frontier logo]()
$108
This Southwest deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/1411:55 pm
ONT
- MDW
Nonstop3h 50m
Southwest
Deal found 7/8![Southwest logo]()
$112
This Trip.com deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/43:40 pm
ONT
- ORD
1 stop11h 57m
Frontier
Deal found 7/8![Frontier logo]()
$118
This Southwest deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/158:30 am
ONT
- MDW
1 stop8h 40m
Southwest
Deal found 7/8![Southwest logo]()
$122
This American Airlines deal was found by Cheapflights users on 7/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/82:43 pm
ONT
- ORD
1 stop7h 35m
American Airlines
Deal found 7/9![American Airlines logo]()
$122
This American Airlines deal was found by Cheapflights users on 7/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/104:07 pm
ONT
- ORD
1 stop6h 21m
American Airlines
Deal found 7/8![American Airlines logo]()
$123
This Super.com deal was found by Cheapflights users on 7/7. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/88:17 am
ONT
- MDW
1 stop7h 09m
Frontier
Deal found 7/7![Frontier logo]()
$124
Find flight deals from Ontario to Chicago
Discover tips and strategies to find the most affordable flight options for your journey from Ontario (ONT) to Chicago (CHI). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated July 9, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $280 (Kiwi.com) |
One-way from | $98 (Trip.com) |
Popular in | December |
Cheapest in | January |
Average price | $447 |
Good round-trip deal | $393 or less |
Good one-way deal | $203 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from Ontario to Chicago that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated July 9, 2026.
Use the filters below to find and compare flights from Ontario to Chicago that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
OntarioChicago
ONT - MDW
ONTMDW
Ontario
Sun 9/27
11:55 pm-5:45 am
Nonstop3h 50m
Chicago Midway
Thu 10/1
6:05 am-9:55 am
1 stop5h 50m
$345
OntarioChicago
ONT - MDW
ONTMDW
Ontario
Mon 10/5
8:20 am-5:45 pm
2 stops7h 25m
Chicago Midway
Fri 10/9
11:55 am-2:10 pm
Nonstop4h 15m
$346
OntarioChicago
ONT - ORD
ONTORD
Ontario
Thu 10/1
7:00 am-1:10 pm
Nonstop4h 10m
Chicago O'Hare Intl
Mon 10/5
8:20 pm-10:49 pm
Nonstop4h 29m
$355
OntarioChicago
ONT - MDW
ONTMDW
Ontario
Wed 9/9
6:40 am-5:10 pm
2 stops8h 30m
Chicago Midway
Sun 9/13
5:25 am-9:30 am
1 stop6h 05m
$360
OntarioChicago
ONT - MDW
ONTMDW
Ontario
Thu 8/6
5:15 am-2:35 pm
2 stops7h 20m
Chicago Midway
Thu 8/13
5:40 am-9:20 am
1 stop5h 40m
$360
OntarioChicago
ONT - ORD
ONTORD
Ontario
Tue 9/1
1:06 pm-9:33 pm
1 stop6h 27m
Chicago O'Hare Intl
Thu 9/3
7:44 pm-11:34 pm
1 stop5h 50m
$371
OntarioChicago
ONT - MDW
ONTMDW
Ontario
Sun 8/9
12:40 pm-10:45 pm
1 stop8h 05m
Chicago Midway
Wed 8/12
5:15 pm-10:05 pm
1 stop6h 50m
$371
OntarioChicago
ONT - RFD
ONTRFD
Ontario
Thu 9/24
6:00 am-8:52 am
2 stops24h 52m
Chicago Greater Rockford
Sun 9/27
9:29 pm-10:21 am
1 stop14h 52m
$373
OntarioChicago
ONT - MDW
ONTMDW
Ontario
Sun 8/9
10:00 pm-9:59 am
1 stop9h 59m
Chicago Midway
Wed 8/12
12:46 pm-11:34 pm
2 stops12h 48m
$376
OntarioChicago
ONT - ORD
ONTORD
Ontario
Wed 9/30
6:00 pm-8:30 am
2 stops12h 30m
Chicago O'Hare Intl
Sat 10/3
8:25 am-4:35 pm
2 stops10h 10m
$382
Showing 1-10 of 56 resultsSorted by cheapest first
Compare providers for flights from Ontario to Chicago
Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Ontario to Chicago in July.
| Provider | Price Accuracy | Trust Score* |
|---|---|---|
| Price Accuracy1 star | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy2 stars | Trust Score*3 stars | |
| Price Accuracy- | Trust Score*1 star |
- Most accurate provider: When it comes to deals on Ontario-Chicago flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Ontario-Chicago flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Ontario-Chicago flight searches over the past month and is updated monthly.
- Most trusted provider: When it comes to deals on Ontario-Chicago flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Ontario-Chicago flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.
Best time to book a flight from Ontario to Chicago
Have a flexible travel schedule? Discover the best time to fly to Chicago from Ontario with our price prediction graph.
ONT-CHI
ONT-MDW
ONT-ORD
ONT-RFD
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.
Cheapflights Insights
Everything you need to know about your flight from Ontario to Chicago
ONT-CHI
ONT-MDW
ONT-ORD
ONT-RFD
What is the cheapest month to book a flight from Ontario to Chicago?
Currently, September is the cheapest month in which you can book a flight from Ontario to Chicago (average of $102). Flying from Ontario to Chicago in March is currently the most expensive (average of $186). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.
What is the cheapest time of day to fly from ONT to CHI?
Find hourly flight availability from Ontario to Chicago. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated July 9, 2026.
When flying from Ontario to Chicago, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.
Weekly flight availability from Ontario to Chicago
Explore weekly flight availability from Ontario to Chicago. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated July 9, 2026.
The most flights from ONT to CHI are scheduled on a Monday (4 on average). You will have fewer flight options on Friday, which is when the least amount of flights are scheduled (2 on average).
How much does it cost to fly round-trip from Ontario to Chicago?
How far ahead should I book a flight from Ontario to Chicago?
The best time to book flights from Ontario to Chicago is 74 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.
The best insider tips for Ontario to Chicago flights
AI-powered summary based on content written by travel experts. AI can make mistakes.
Cheapflights partnered with top experts to bring you the best recommendations for your Ontario to Chicago trip
Our travel experts
Reviews of airlines servicing Chicago
Get insights into the airlines that provide service to Chicago. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Chicago. Reviews last updated July 9, 2026.
See what other customers who have flown with Southwest,Delta, andUnited Airlines from Ontario to Chicago have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Crew
8.6
Food
7.0
Overall
7.9
Entertainment
7.5
Comfort
8.0
Boarding
8.1
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Crew
8.6
Food
7.0
Overall
7.9
Entertainment
7.5
Comfort
8.0
Boarding
8.1
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Crew
8.6
Food
7.0
Overall
7.9
Entertainment
7.5
Comfort
8.0
Boarding
8.1
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Crew
8.6
Food
7.0
Overall
7.9
Entertainment
7.5
Comfort
8.0
Boarding
8.1
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Crew
8.6
Food
7.0
Overall
7.9
Entertainment
7.5
Comfort
8.0
Boarding
8.1
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Related info for your journey
Find useful and relevant information for your journey from Ontario to Chicago. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
Traveling to a place near Chicago?
Book flights to Chicago if you plan to visit one of these locationsBenton Harbor
Hammond
Lansing
Merrillville
Valparaiso
Porter
Browse thousands of different options on Cheapflights for your next trip
Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.
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Alternative routes for Ontario to Chicago
See prices for flight routes from nearby airports that may be better suited for you.
Other flights to Chicago
Explore flights to Chicago departing from other origins. Flights are based on user searches made on Cheapflights and were last updated on July 9, 2026.
Complete your trip
Complete your trip to Chicago by adding a car rental and/or hotel reservation to your travel itinerary.
Search flights from Ontario to Chicago by cabin class
Find flights from Ontario to Chicago, based on your preferred cabin class, be it economy, premium economy, business, or first class.
Ontario and Chicago flights
Browse other Ontario and Chicago flight options. Last updated on July 9, 2026.
Other flights from Ontario
Browse through other flights departing from Ontario. Flights are based on user searches made on Cheapflights and were last updated on July 9, 2026.
Popular flight searches
Check out other popular destinations found by fellow travelers in 2026
Top 5 airlines flying from Ontario to Chicago
Discover the top 5 airlines that operate flights from Ontario to Chicago. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated July 9, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$117 | Average$258 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$258 | Average$430 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$260 | Average$446 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$262 | Average$448 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$276 | Average$516 | FlexibilityNo cancel fee | On-time71% |