$91+ Cheap flights from Boston (BOS) to St. Charles, MO
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 8/23. Fares are subject to change and may not be available on all flights or dates of travel.
BOS — STL
Aug 31 — Sep 71
Round-trip
1 adult, Economy
We work with more than 300 partners to bring you better travel deals
Find cheap flights from Boston to St. Charles 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 Boston Logan Intl to St. Charles are usually found in January or August, booked 75 days in advance, depart on a Wednesday or Thursday and return on a Wednesday
Cheap flight deals from Boston to St. Charles
Cheapest
Best
Last-minute
One-way
Cheapest flights from Boston to St. CharlesExplore the most affordable flight options available from Boston to St. Charles. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 1, 2026.
Explore the most affordable flight options available from Boston to St. Charles. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 1, 2026.
This Kiwi.com deal was found by Cheapflights users on 7/28. 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 8/1510:04 am
BOS
- STL
1 stop14h 55m
Frontier
Mon 8/246:17 pm
STL
- BOS
1 stop16h 30m
Frontier
Deal found 7/28![Frontier logo]()
$328
This American Airlines deal was found by Cheapflights users on 7/28. 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.
Tue 9/15:45 pm
BOS
- STL
1 stop7h 29m
American Airlines
Wed 9/305:00 am
STL
- BOS
1 stop8h 08m
American Airlines
Deal found 7/28![American Airlines logo]()
$330
This Kiwi.com deal was found by Cheapflights users on 7/28. 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 8/2910:04 am
BOS
- STL
1 stop7h 07m
Frontier
Tue 9/15:27 pm
STL
- BOS
2 stops38h 42m
Frontier
Deal found 7/28![Frontier logo]()
$331
This Southwest deal was found by Cheapflights users on 7/28. 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 9/305:35 am
BOS
- STL
Nonstop2h 50m
Southwest
Thu 10/14:30 pm
STL
- BOS
2 stops6h 35m
Southwest
Deal found 7/28![Southwest logo]()
$332
This Kiwi.com deal was found by Cheapflights users on 7/30. 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 9/310:04 am
BOS
- STL
1 stop7h 07m
Frontier
Sun 9/66:17 pm
STL
- BOS
2 stops16h 33m
Frontier
Deal found 7/30![Frontier logo]()
$334
This Kiwi.com deal was found by Cheapflights users on 7/31. 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.
Fri 8/289:36 am
BOS
- STL
1 stop8h 46m
Frontier
Fri 9/46:17 pm
STL
- BOS
1 stop16h 30m
Frontier
Deal found 7/31![Frontier logo]()
$336
This Delta deal was found by Cheapflights users on 7/28. 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.
Thu 8/205:30 am
BOS
- STL
1 stop5h 24m
Delta
Wed 8/262:10 pm
STL
- BOS
1 stop4h 48m
Delta
Deal found 7/28![Delta logo]()
$337
This Southwest deal was found by Cheapflights users on 7/29. 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 8/125:35 am
BOS
- STL
Nonstop2h 50m
Southwest
Wed 8/191:20 pm
STL
- BOS
Nonstop2h 35m
Southwest
Deal found 7/29![Southwest logo]()
$338
This deal was found by Cheapflights users on 7/30. 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.
Fri 8/215:30 am
BOS
- STL
1 stop5h 24m
Delta
Sat 8/226:09 pm
STL
- BOS
1 stop4h 50m
Delta
Deal found 7/30![Delta logo]()
$342
This American Airlines deal was found by Cheapflights users on 7/27. 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.
Wed 9/27:09 am
BOS
- STL
Nonstop3h 04m
American Airlines
Thu 9/106:00 pm
STL
- BOS
Nonstop2h 47m
American Airlines
Deal found 7/27![American Airlines logo]()
$343
This Kiwi.com deal was found by Cheapflights users on 7/29. 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.
Fri 9/49:36 am
BOS
- STL
1 stop8h 46m
Frontier
Sun 9/66:17 pm
STL
- BOS
1 stop16h 30m
Frontier
Deal found 7/29![Frontier logo]()
$344
This Kiwi.com deal was found by Cheapflights users on 7/31. 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.
Fri 8/219:36 am
BOS
- STL
1 stop8h 46m
Frontier
Mon 8/246:17 pm
STL
- BOS
1 stop16h 30m
Frontier
Deal found 7/31![Frontier logo]()
$345
Best flights from Boston to St. CharlesDiscover carefully curated flight deals from Boston to St. Charles that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated August 1, 2026.
Discover carefully curated flight deals from Boston to St. Charles that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated August 1, 2026.
This Southwest deal was found by Cheapflights users on 7/28. 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 9/3010:50 am
BOS
- STL
2 stops8h 05m
Southwest
Thu 10/15:50 pm
STL
- BOS
1 stop5h 00m
Southwest
Deal found 7/28![Southwest logo]()
$342
This Delta deal was found by Cheapflights users on 7/30. 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 9/49:00 am
BOS
- STL
1 stop7h 38m
Delta
Mon 9/75:23 pm
STL
- BOS
1 stop7h 02m
Delta
Deal found 7/30![Delta logo]()
$370
This United Airlines deal was found by Cheapflights users on 7/30. 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 10/18:00 am
BOS
- STL
1 stop5h 13m
United Airlines
Mon 10/53:11 pm
STL
- BOS
2 stops7h 58m
United Airlines
Deal found 7/30![United Airlines logo]()
$432
This Southwest deal was found by Cheapflights users on 7/28. 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 8/195:25 am
BOS
- STL
2 stops7h 45m
Southwest
Wed 8/192:45 pm
STL
- BOS
1 stop6h 25m
Southwest
Deal found 7/28![Southwest logo]()
$342
This Southwest deal was found by Cheapflights users on 7/28. 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 8/137:40 am
BOS
- STL
2 stops8h 30m
Southwest
Tue 8/1810:25 am
STL
- BOS
Nonstop2h 35m
Southwest
Deal found 7/28![Southwest logo]()
$353
This United Airlines deal was found by Cheapflights users on 7/28. 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 9/2410:36 am
BOS
- STL
1 stop6h 07m
United Airlines
Tue 9/298:00 am
STL
- BOS
2 stops7h 59m
United Airlines
Deal found 7/28![United Airlines logo]()
$432
This Southwest deal was found by Cheapflights users on 7/31. 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 10/85:25 am
BOS
- STL
Nonstop3h 00m
Southwest
Mon 10/195:55 am
STL
- BOS
Nonstop2h 35m
Southwest
Deal found 7/31![Southwest logo]()
$369
This Delta deal was found by Cheapflights users on 7/31. 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 8/119:55 am
BOS
- STL
1 stop5h 38m
Delta
Sat 8/226:09 pm
STL
- BOS
1 stop4h 50m
Delta
Deal found 7/31![Delta logo]()
$471
This United Airlines deal was found by Cheapflights users on 7/27. 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 9/47:30 am
BOS
- STL
2 stops9h 08m
United Airlines
Mon 9/77:00 am
STL
- BOS
1 stop6h 22m
United Airlines
Deal found 7/27![United Airlines logo]()
$484
This Southwest deal was found by Cheapflights users on 7/28. 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 9/1112:40 pm
BOS
- STL
2 stops7h 30m
Southwest
Sun 9/134:20 pm
STL
- BOS
1 stop6h 20m
Southwest
Deal found 7/28![Southwest logo]()
$424
This United Airlines deal was found by Cheapflights users on 7/30. 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 10/225:45 am
BOS
- STL
2 stops9h 32m
United Airlines
Sun 10/256:00 am
STL
- BOS
1 stop5h 26m
United Airlines
Deal found 7/30![United Airlines logo]()
$519
This Southwest deal was found by Cheapflights users on 7/31. 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 8/247:40 am
BOS
- STL
2 stops8h 30m
Southwest
Wed 8/2610:45 am
STL
- BOS
2 stops6h 50m
Southwest
Deal found 7/31![Southwest logo]()
$478
Last-minute flights from Boston to St. CharlesDiscover last-minute flight deals from Boston to St. Charles. Data last updated August 1, 2026 and is based on user searches.
Discover last-minute flight deals from Boston to St. Charles. Data last updated August 1, 2026 and is based on user searches.
This Super.com deal was found by Cheapflights users on 7/27. 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 8/411:52 am
BOS
- STL
1 stop6h 45m
Frontier
Fri 8/74:09 pm
STL
- BOS
1 stop16h 00m
Frontier
Deal found 7/27![Frontier logo]()
$349
This Southwest deal was found by Cheapflights users on 7/29. 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 8/125:35 am
BOS
- STL
Nonstop2h 50m
Southwest
Wed 8/191:20 pm
STL
- BOS
Nonstop2h 35m
Southwest
Deal found 7/29![Southwest logo]()
$338
This Kiwi.com deal was found by Cheapflights users on 7/28. 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 8/1510:04 am
BOS
- STL
1 stop14h 55m
Frontier
Mon 8/246:17 pm
STL
- BOS
1 stop16h 30m
Frontier
Deal found 7/28![Frontier logo]()
$328
This Southwest deal was found by Cheapflights users on 7/28. 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 8/195:25 am
BOS
- STL
2 stops7h 45m
Southwest
Wed 8/191:20 pm
STL
- BOS
Nonstop2h 35m
Southwest
Deal found 7/28![Southwest logo]()
$332
This Delta deal was found by Cheapflights users on 7/28. 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.
Thu 8/205:30 am
BOS
- STL
1 stop5h 24m
Delta
Wed 8/262:10 pm
STL
- BOS
1 stop4h 48m
Delta
Deal found 7/28![Delta logo]()
$337
This deal was found by Cheapflights users on 7/30. 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.
Fri 8/215:30 am
BOS
- STL
1 stop5h 24m
Delta
Sat 8/226:09 pm
STL
- BOS
1 stop4h 50m
Delta
Deal found 7/30![Delta logo]()
$342
This Kiwi.com deal was found by Cheapflights users on 7/31. 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.
Fri 8/219:36 am
BOS
- STL
1 stop8h 46m
Frontier
Mon 8/246:17 pm
STL
- BOS
1 stop16h 30m
Frontier
Deal found 7/31![Frontier logo]()
$345
This Kiwi.com deal was found by Cheapflights users on 7/28. 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 8/2210:04 am
BOS
- STL
1 stop7h 07m
Frontier
Mon 8/247:58 pm
STL
- BOS
2 stops14h 49m
Frontier
Deal found 7/28![Frontier logo]()
$343
This Southwest deal was found by Cheapflights users on 7/28. 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 8/255:25 am
BOS
- STL
2 stops6h 55m
Southwest
Wed 8/266:30 am
STL
- BOS
2 stops7h 10m
Southwest
Deal found 7/28![Southwest logo]()
$347
This Kiwi.com deal was found by Cheapflights users on 7/31. 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.
Fri 8/289:36 am
BOS
- STL
1 stop8h 46m
Frontier
Fri 9/46:17 pm
STL
- BOS
1 stop16h 30m
Frontier
Deal found 7/31![Frontier logo]()
$336
This Kiwi.com deal was found by Cheapflights users on 7/28. 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 8/2910:04 am
BOS
- STL
1 stop7h 07m
Frontier
Tue 9/15:27 pm
STL
- BOS
2 stops38h 42m
Frontier
Deal found 7/28![Frontier logo]()
$331
One-way flights from Boston to St. CharlesSearch for one-way flight options from Boston to St. Charles. Find affordable one-way fares based on user searches. Data last updated August 1, 2026.
Search for one-way flight options from Boston to St. Charles. Find affordable one-way fares based on user searches. Data last updated August 1, 2026.
This Kiwi.com deal was found by Cheapflights users on 7/27. 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 8/2312:45 pm
BOS
- STL
1 stop29h 37m
Frontier
Deal found 7/27![Frontier logo]()
$91
This Kiwi.com deal was found by Cheapflights users on 7/30. 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 9/2212:52 pm
BOS
- STL
2 stops31h 25m
Frontier
Deal found 7/30![Frontier logo]()
$116
This Priceline deal was found by Cheapflights users on 7/30. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/2910:04 am
BOS
- STL
1 stop7h 07m
Frontier
Deal found 7/30![Frontier logo]()
$119
This Super.com deal was found by Cheapflights users on 7/31. 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 8/319:36 am
BOS
- STL
1 stop8h 46m
Frontier
Deal found 7/31![Frontier logo]()
$124
This Frontier deal was found by Cheapflights users on 7/27. 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.
Thu 8/279:36 am
BOS
- STL
1 stop8h 46m
Frontier
Deal found 7/27![Frontier logo]()
$125
This Kiwi.com deal was found by Cheapflights users on 7/30. 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 10/111:17 am
BOS
- STL
2 stops33h 00m
Frontier
Deal found 7/30![Frontier logo]()
$127
This Kiwi.com deal was found by Cheapflights users on 7/31. 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.
Fri 10/212:54 pm
BOS
- STL
2 stops31h 23m
Frontier
Deal found 7/31![Frontier logo]()
$130
This Frontier deal was found by Cheapflights users on 7/29. 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.
Thu 10/2910:11 am
BOS
- STL
1 stop10h 28m
Frontier
Deal found 7/29![Frontier logo]()
$131
Find flight deals from Boston to St. Charles
Keep the following information in mind while searching for Boston to St. Charles flight deals. Data was last updated August 1, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $328 (Kiwi.com) |
One-way from | $91 (Kiwi.com) |
Popular in | July |
Cheapest in | January |
Average price | $431 |
Cheapflights Fare Finder
Customize your flight search to find flights from Boston to St. Charles 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 August 1, 2026.
Use the filters below to find and compare flights from Boston to St. Charles that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Wed 9/30
10:50 am-5:55 pm
2 stops8h 05m
Lambert-St Louis
Thu 10/1
5:50 pm-11:50 pm
1 stop5h 00m
$342
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Wed 8/19
5:25 am-12:10 pm
2 stops7h 45m
Lambert-St Louis
Wed 8/19
2:45 pm-10:10 pm
1 stop6h 25m
$342
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Thu 8/13
7:40 am-3:10 pm
2 stops8h 30m
Lambert-St Louis
Tue 8/18
10:25 am-2:00 pm
Nonstop2h 35m
$353
Quickest round-trip
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Thu 10/8
5:25 am-7:25 am
Nonstop3h 00m
Lambert-St Louis
Mon 10/19
5:55 am-9:30 am
Nonstop2h 35m
$369
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Fri 9/4
9:00 am-3:38 pm
1 stop7h 38m
Lambert-St Louis
Mon 9/7
5:23 pm-1:25 am
1 stop7h 02m
$370
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Fri 9/11
12:40 pm-7:10 pm
2 stops7h 30m
Lambert-St Louis
Sun 9/13
4:20 pm-11:40 pm
1 stop6h 20m
$424
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Thu 10/1
8:00 am-12:13 pm
1 stop5h 13m
Lambert-St Louis
Mon 10/5
3:11 pm-12:09 am
2 stops7h 58m
$432
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Thu 9/24
10:36 am-3:43 pm
1 stop6h 07m
Lambert-St Louis
Tue 9/29
8:00 am-4:59 pm
2 stops7h 59m
$432
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Tue 8/11
9:55 am-2:33 pm
1 stop5h 38m
Lambert-St Louis
Sat 8/22
6:09 pm-11:59 pm
1 stop4h 50m
$471
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Mon 8/24
7:40 am-3:10 pm
2 stops8h 30m
Lambert-St Louis
Wed 8/26
10:45 am-6:35 pm
2 stops6h 50m
$478
Showing 1-10 of 22 resultsSorted by cheapest first
Best time to book a flight from Boston to St. Charles
Have a flexible travel schedule? Discover the best time to fly to St. Charles from Boston with our price prediction graph.
BOS-STL
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 Boston to St. Charles
BOS-CH5
BOS-STL
What is the cheapest time of day to fly from BOS to CH5?
Find hourly flight availability from Boston to St. Charles. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated August 1, 2026.
It’s optimal to fly from Boston to St. Charles in the evening. By choosing this option you can save up to 11% on the cost of your flight, compared to a flight in the afternoon.
How much does it cost to fly round-trip from Boston to St. Charles?
Airfare is typical for this route at the moment.
Boston to St. Charles flights typically cost between $321 and $567 in August.The cheapest round-trip price found within the last 5 days was $328 on Frontier (Aug 15-Aug 24).
What is the cheapest day to fly from Boston to St. Charles?
Use this chart to determine the cheapest time to fly round-trip from Boston to St. Charles. Price data was last updated on July 25, 2026.
Travelers seeking maximum savings on their Boston to St. Charles flight should consider departing on Wednesday at noon when fares are most often at their lowest. Sunday at noon flights should be avoided if possible as fares are typically the most expensive at this time.
Reviews of airlines servicing St. Charles
Get insights into the airlines that provide service to St. Charles. 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 St. Charles. Reviews last updated August 1, 2026.
Peruse reviews from past customers who have flown with Southwest,Delta, andAmerican Airlines from Boston to St. Charles to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Crew
8.6
Overall
8.0
Comfort
8.0
Food
7.0
Boarding
8.1
Entertainment
7.5
Reviews
1 / 20
8.0
ExcellentLibby,Jun 2026
TUS - LAS
Crew
8.6
Overall
8.0
Comfort
8.0
Food
7.0
Boarding
8.1
Entertainment
7.5
Reviews
1 / 20
8.0
ExcellentLibby,Jun 2026
TUS - LAS
Crew
8.6
Overall
8.0
Comfort
8.0
Food
7.0
Boarding
8.1
Entertainment
7.5
Reviews
1 / 20
8.0
ExcellentLibby,Jun 2026
TUS - LAS
Crew
8.6
Overall
8.0
Comfort
8.0
Food
7.0
Boarding
8.1
Entertainment
7.5
Reviews
1 / 20
8.0
ExcellentLibby,Jun 2026
TUS - LAS
Crew
8.6
Overall
8.0
Comfort
8.0
Food
7.0
Boarding
8.1
Entertainment
7.5
Reviews
1 / 20
8.0
ExcellentLibby,Jun 2026
TUS - LAS
Crew
8.6
Overall
8.0
Comfort
8.0
Food
7.0
Boarding
8.1
Entertainment
7.5
Reviews
1 / 20
8.0
ExcellentLibby,Jun 2026
TUS - LAS
Related info for your journey
Find useful and relevant information for your journey from Boston to St. Charles. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
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.
Alternative routes
Complete your trip
Flights by cabin class
Other flight options
Other flights from Boston
Popular flights
Top destinations
Alternative routes for Boston to St. Charles
See prices for flight routes from nearby airports that may be better suited for you.
Complete your trip
Complete your trip to St. Charles by adding a car rental and/or hotel reservation to your travel itinerary.
Search flights from Boston to St. Charles by cabin class
Find flights from Boston to St. Charles, based on your preferred cabin class, be it economy, premium economy, business, or first class.
Boston and St. Charles flights
Browse other Boston and St. Charles flight options. Last updated on August 1, 2026.
Other flights from Boston
Browse through other flights departing from Boston. Flights are based on user searches made on Cheapflights and were last updated on August 1, 2026.
Popular flight searches
Check out other popular destinations found by fellow travelers in 2026
Boston to St. Charles flights
Consider these flights traveling from Boston to St. Charles.
Top 6 airlines flying from Boston to St. Charles
Discover the top 6 airlines that operate flights from Boston to St. Charles. 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 August 1, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$90 | Average$255 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$148 | Average$516 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$205 | Average$408 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$298 | Average$543 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$327 | Average$437 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$332 | Average$501 | FlexibilityNo cancel fee | On-time63% |