$43+ Cheap flights from Ontario to San Francisco (ONT - SFO)
This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 9/24. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — SFO
Oct 18 — Oct 251
Round-trip
1 adult, Economy
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Find cheap flights from Ontario to San Francisco 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 San Francisco are usually found in October or August, booked 73 days in advance, depart on a Friday or Saturday and return on a Monday
Cheap flight deals from Ontario to San Francisco
Cheapest
Best
Last-minute
One-way
Cheapest flights from Ontario to San FranciscoExplore the most affordable flight options available from Ontario to San Francisco. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 18, 2026.
Explore the most affordable flight options available from Ontario to San Francisco. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 18, 2026.
This Expedia deal was found by Cheapflights users on 9/15. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/2312:01 pm -
Nonstop1h 31m
Fri 10/306:02 pm -
Nonstop1h 26m
Deal found 9/15![Frontier logo]()
$60
This Trip.com deal was found by Cheapflights users on 9/13. 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.
Fri 10/2312:01 pm -
Nonstop1h 31m
Fri 10/236:02 pm -
Nonstop1h 38m
Deal found 9/13![Frontier logo]()
$65
This Super.com deal was found by Cheapflights users on 9/13. 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.
Thu 9/2412:07 pm -
Nonstop1h 36m
Fri 9/256:02 pm -
Nonstop1h 34m
Deal found 9/13![Frontier logo]()
$76
This Mytrip deal was found by Cheapflights users on 9/14. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/2412:07 pm -
Nonstop1h 36m
Thu 9/246:02 pm -
Nonstop1h 34m
Deal found 9/14![Frontier logo]()
$77
This deal was found by Cheapflights users on 9/16. 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 is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/238:31 pm -
Nonstop1h 33m
Mon 11/3010:59 pm -
Nonstop1h 30m
Deal found 9/16![Frontier logo]()
$81
This Frontier deal was found by Cheapflights users on 9/14. 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 10/3012:01 pm -
Nonstop1h 35m
Sun 11/16:02 pm -
Nonstop1h 26m
Deal found 9/14![Frontier logo]()
$87
This Justfly.com deal was found by Cheapflights users on 9/15. 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 Justfly.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/2412:07 pm -
Nonstop1h 36m
Mon 9/286:02 pm -
Nonstop1h 34m
Deal found 9/15![Frontier logo]()
$89
This Frontier deal was found by Cheapflights users on 9/14. 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 10/2312:01 pm -
Nonstop1h 31m
Sun 10/256:02 pm -
Nonstop1h 38m
Deal found 9/14![Frontier logo]()
$95
This Trip.com deal was found by Cheapflights users on 9/13. 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.
Thu 9/2412:07 pm -
Nonstop1h 36m
Sun 10/46:02 pm -
Nonstop1h 34m
Deal found 9/13![Frontier logo]()
$98
This Cheapflightsfares deal was found by Cheapflights users on 9/17. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/27:26 pm -
Nonstop1h 34m
Tue 12/89:56 pm -
Nonstop1h 27m
Deal found 9/17![Frontier logo]()
$100
This FlightHub deal was found by Cheapflights users on 9/17. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/57:26 pm -
Nonstop1h 35m
Tue 12/89:56 pm -
Nonstop1h 27m
Deal found 9/17![Frontier logo]()
$105
Best flights from Ontario to San FranciscoDiscover carefully curated flight deals from Ontario to San Francisco that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated September 18, 2026.
Discover carefully curated flight deals from Ontario to San Francisco that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated September 18, 2026.
This Southwest deal was found by Cheapflights users on 9/17. 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 10/209:15 am -
2 stops7h 55m
Sun 10/256:15 am -
1 stop6h 00m
Deal found 9/17![Southwest logo]()
$264
This United Airlines deal was found by Cheapflights users on 9/17. 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 10/41:52 pm -
Nonstop1h 29m
Wed 10/147:00 pm -
Nonstop1h 31m
Deal found 9/17![United Airlines logo]()
$289
This Southwest deal was found by Cheapflights users on 9/14. 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 10/295:20 am -
2 stops6h 00m
Sat 10/3111:25 am -
1 stop5h 35m
Deal found 9/14![Southwest logo]()
$269
This United Airlines deal was found by Cheapflights users on 9/15. 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.
Sat 9/264:03 pm -
Nonstop1h 47m
Tue 10/68:40 am -
Nonstop1h 43m
Deal found 9/15![United Airlines logo]()
$289
This Southwest deal was found by Cheapflights users on 9/14. 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 12/38:40 am -
2 stops7h 35m
Sat 12/55:00 am -
2 stops6h 20m
Deal found 9/14![Southwest logo]()
$275
This United Airlines deal was found by Cheapflights users on 9/13. 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 9/206:08 am -
Nonstop1h 27m
Tue 9/2212:30 pm -
Nonstop1h 31m
Deal found 9/13![United Airlines logo]()
$317
This United Airlines deal was found by Cheapflights users on 9/13. 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 9/2411:10 am -
Nonstop1h 33m
Tue 9/294:10 pm -
Nonstop1h 31m
Deal found 9/13![United Airlines logo]()
$317
This Southwest deal was found by Cheapflights users on 9/14. 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 11/56:50 pm -
1 stop5h 20m
Sun 11/83:15 pm -
2 stops7h 45m
Deal found 9/14![Southwest logo]()
$335
This United Airlines deal was found by Cheapflights users on 9/15. 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 10/301:35 pm -
Nonstop1h 30m
Sun 11/111:00 am -
Nonstop1h 29m
Deal found 9/15![United Airlines logo]()
$326
This United Airlines deal was found by Cheapflights users on 9/17. 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 10/16:32 pm -
Nonstop1h 47m
Sat 10/34:15 pm -
Nonstop1h 31m
Deal found 9/17![United Airlines logo]()
$329
This United Airlines deal was found by Cheapflights users on 9/17. 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 9/241:52 pm -
Nonstop1h 29m
Sun 9/279:25 pm -
Nonstop1h 34m
Deal found 9/17![United Airlines logo]()
$337
Last-minute flights from Ontario to San FranciscoDiscover last-minute flight deals from Ontario to San Francisco. Data last updated September 18, 2026 and is based on user searches.
Discover last-minute flight deals from Ontario to San Francisco. Data last updated September 18, 2026 and is based on user searches.
This deal was found by Cheapflights users on 9/13. 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 is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/2210:04 am -
1 stop4h 25m
Mon 9/286:02 pm -
Nonstop1h 34m
Deal found 9/13![Frontier logo]()
$105
This Super.com deal was found by Cheapflights users on 9/13. 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.
Thu 9/2412:07 pm -
Nonstop1h 36m
Fri 9/256:02 pm -
Nonstop1h 34m
Deal found 9/13![Frontier logo]()
$76
This Mytrip deal was found by Cheapflights users on 9/14. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/2412:07 pm -
Nonstop1h 36m
Thu 9/246:02 pm -
Nonstop1h 34m
Deal found 9/14![Frontier logo]()
$77
This Justfly.com deal was found by Cheapflights users on 9/15. 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 Justfly.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/2412:07 pm -
Nonstop1h 36m
Mon 9/286:02 pm -
Nonstop1h 34m
Deal found 9/15![Frontier logo]()
$89
This Trip.com deal was found by Cheapflights users on 9/13. 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.
Thu 9/2412:07 pm -
Nonstop1h 36m
Sun 10/46:02 pm -
Nonstop1h 34m
Deal found 9/13![Frontier logo]()
$98
This Expedia deal was found by Cheapflights users on 9/15. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/2312:01 pm -
Nonstop1h 31m
Fri 10/306:02 pm -
Nonstop1h 26m
Deal found 9/15![Frontier logo]()
$60
This Trip.com deal was found by Cheapflights users on 9/13. 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.
Fri 10/2312:01 pm -
Nonstop1h 31m
Fri 10/236:02 pm -
Nonstop1h 38m
Deal found 9/13![Frontier logo]()
$65
This Frontier deal was found by Cheapflights users on 9/14. 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 10/2312:01 pm -
Nonstop1h 31m
Sun 10/256:02 pm -
Nonstop1h 38m
Deal found 9/14![Frontier logo]()
$95
This Frontier deal was found by Cheapflights users on 9/14. 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 10/3012:01 pm -
Nonstop1h 35m
Sun 11/16:02 pm -
Nonstop1h 26m
Deal found 9/14![Frontier logo]()
$87
One-way flights from Ontario to San FranciscoSearch for one-way flight options from Ontario to San Francisco. Find affordable one-way fares based on user searches. Data last updated September 18, 2026.
Search for one-way flight options from Ontario to San Francisco. Find affordable one-way fares based on user searches. Data last updated September 18, 2026.
This Super.com deal was found by Cheapflights users on 9/15. 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.
Thu 9/2412:07 pm -
Nonstop1h 36m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/15![Frontier logo]()
$43
This Super.com deal was found by Cheapflights users on 9/18. 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.
Tue 12/17:26 pm -
Nonstop1h 34m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/18![Frontier logo]()
$50
This Super.com deal was found by Cheapflights users on 9/17. 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 12/167:26 pm -
Nonstop1h 35m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/17![Frontier logo]()
$51
This CheapOair deal was found by Cheapflights users on 9/15. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/97:11 am -
Nonstop1h 33m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/15![Frontier logo]()
$52
This Jetabroad deal was found by Cheapflights users on 9/17. 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 Jetabroad is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/27:26 pm -
Nonstop1h 34m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/17![Frontier logo]()
$53
This FlightHub deal was found by Cheapflights users on 9/18. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/1912:01 pm -
Nonstop1h 31m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/18![Frontier logo]()
$57
This United Airlines deal was found by Cheapflights users on 9/17. 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 11/266:00 am -
Nonstop1h 30m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/17![United Airlines logo]()
$59
This Super.com deal was found by Cheapflights users on 9/16. 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.
Mon 10/512:07 pm -
Nonstop1h 36m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/16![Frontier logo]()
$68
Find flight deals from Ontario to San Francisco
Discover tips and strategies to find the most affordable flight options for your journey from Ontario (ONT) to San Francisco (SFO). 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 September 18, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $60 (Expedia) |
One-way from | $43 (Super.com) |
Popular in | February |
Cheapest in | October |
Average price | $183 |
Good round-trip deal | $184 or less |
Good one-way deal | $110 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from Ontario to San Francisco 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 7,457,451 searches. Data last updated September 18, 2026.
Use the filters below to find and compare flights from Ontario to San Francisco that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
OntarioSan Francisco
ONT Ontario - SFO San Francisco
ONTSFO
Ontario
Tue 12/15
3:20 pm-9:20 pm
1 stop6h 00m
San Francisco
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$106
Quickest round-trip
OntarioSan Francisco
ONT Ontario - SFO San Francisco
ONTSFO
Ontario
Sat 12/5
11:20 am-12:50 pm
Nonstop1h 30m
San Francisco
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$114
OntarioSan Francisco
ONT Ontario - SFO San Francisco
ONTSFO
Ontario
Wed 10/7
4:03 pm-5:50 pm
Nonstop1h 47m
San Francisco
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$131
OntarioSan Francisco
ONT Ontario - SFO San Francisco
ONTSFO
Ontario
Mon 10/26
1:35 pm-3:05 pm
Nonstop1h 30m
San Francisco
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$134
OntarioSan Francisco
ONT Ontario - SFO San Francisco
ONTSFO
Ontario
Tue 9/29
3:35 pm-9:40 pm
1 stop6h 05m
San Francisco
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$139
OntarioSan Francisco
ONT Ontario - SFO San Francisco
ONTSFO
Ontario
Tue 3/16
5:25 am-12:00 pm
1 stop6h 35m
San Francisco
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$160
OntarioSan Francisco
ONT Ontario - SFO San Francisco
ONTSFO
Ontario
Fri 10/23
4:29 pm-10:37 pm
1 stop6h 08m
San Francisco
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$179
OntarioSan Francisco
ONT Ontario - SFO San Francisco
ONTSFO
Ontario
Fri 12/25
12:50 pm-8:10 pm
2 stops7h 20m
San Francisco
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$188
OntarioSan Francisco
ONT Ontario - SFO San Francisco
ONTSFO
Ontario
Sat 10/10
9:25 am-3:05 pm
2 stops5h 40m
San Francisco
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$195
OntarioSan Francisco
ONT Ontario - SFO San Francisco
ONTSFO
Ontario
Sat 11/14
6:00 am-4:44 pm
2 stops10h 44m
San Francisco
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$197
Showing 1-10 of 23 resultsSorted by cheapest first
Compare providers for flights from Ontario to San Francisco
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 San Francisco in September.
| Provider | Price Accuracy | Trust Score* |
|---|---|---|
| Price Accuracy1 star | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy- | Trust Score*1 star | |
| Price Accuracy- | Trust Score*1 star | |
| Price Accuracy- | 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 Accuracy1 star | Trust Score*3 stars |
- Most accurate provider: When it comes to deals on Ontario-San Francisco flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Ontario-San Francisco flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Ontario-San Francisco flight searches over the past month and is updated monthly.
- Most trusted provider: When it comes to deals on Ontario-San Francisco 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-San Francisco 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 San Francisco
Have a flexible travel schedule? Discover the best time to fly to San Francisco from Ontario with our price prediction graph.
ONT-SFO
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 San Francisco
Prices
Airlines
How far ahead should I book a flight from Ontario to San Francisco?
Booking 72 days in advance of your planned departure date is, on average, the best time to get cheap flights from Ontario to San Francisco. The general trend is that the closer you book to the departure date, the more expensive your flight will be.
What is the cheapest month to book a flight from Ontario to San Francisco?
Currently, October is the cheapest month in which you can book a flight from Ontario to San Francisco (average of $138). Flying from Ontario to San Francisco in February is currently the most expensive (average of $307). 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 SFO?
Find hourly flight availability from Ontario to San Francisco. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated September 18, 2026.
One of the essential ways to save on airfare from Ontario to San Francisco is to remain as flexible as possible. Flights that are in the afternoon tend to be the most expensive. A flight in the evening could potentially save you up to 59% on airfare.
What is the cheapest day to fly from Ontario to San Francisco?
Use this chart to determine the cheapest time to fly round-trip from Ontario to San Francisco. Price data was last updated on September 12, 2026.
Travelers seeking maximum savings on their Ontario to San Francisco flight should consider departing on Friday evenings when fares are most often at their lowest. Monday afternoons flights should be avoided if possible as fares are typically the most expensive at this time.
The best insider tips for Ontario to San Francisco 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 San Francisco trip
Our travel experts
Reviews of airlines servicing San Francisco
Get insights into the airlines that provide service to San Francisco. 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 San Francisco. Reviews last updated September 18, 2026.
See what other customers who have flown with Southwest,Alaska Airlines, andUnited Airlines from Ontario to San Francisco have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Overall
8.0
Boarding
8.1
Crew
8.6
Food
7.0
Entertainment
7.5
Comfort
8.0
Reviews
1 / 20
8.0
ExcellentWalter,Aug 2025
OAK - SAN
Overall
8.0
Boarding
8.1
Crew
8.6
Food
7.0
Entertainment
7.5
Comfort
8.0
Reviews
1 / 20
8.0
ExcellentWalter,Aug 2025
OAK - SAN
Overall
8.0
Boarding
8.1
Crew
8.6
Food
7.0
Entertainment
7.5
Comfort
8.0
Reviews
1 / 20
8.0
ExcellentWalter,Aug 2025
OAK - SAN
Overall
8.0
Boarding
8.1
Crew
8.6
Food
7.0
Entertainment
7.5
Comfort
8.0
Reviews
1 / 20
8.0
ExcellentWalter,Aug 2025
OAK - SAN
Overall
8.0
Boarding
8.1
Crew
8.6
Food
7.0
Entertainment
7.5
Comfort
8.0
Reviews
1 / 20
8.0
ExcellentWalter,Aug 2025
OAK - SAN
Overall
8.0
Boarding
8.1
Crew
8.6
Food
7.0
Entertainment
7.5
Comfort
8.0
Reviews
1 / 20
8.0
ExcellentWalter,Aug 2025
OAK - SAN
Related info for your journey
Find useful and relevant information for your journey from Ontario to San Francisco. 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 San Francisco?
Book flights to San Francisco if you plan to visit one of these locationsSouth San Francisco
Santa Clara
Santa Cruz
Walnut Creek
Emeryville
San Bruno
Burlingame
Rancho Cordova
Roseville
Fairfield
Hayward
Cupertino
Newark
San Ramon
Redwood City
Manteca
Vallejo
San Carlos
Turlock
Davis
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Ontario and San Francisco flights
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Top 5 airlines flying from Ontario to San Francisco
Discover the top 5 airlines that operate flights from Ontario to San Francisco. 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 7,457,451 searches. Data last updated September 18, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$50 | Average$155 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$91 | Average$192 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$100 | Average$244 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$120 | Average$188 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$226 | Average$344 | FlexibilityNo cancel fee | On-time63% |