$84+ 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 4/1. Fares are subject to change and may not be available on all flights or dates of travel.
BOS — STL
Apr 11 — Apr 181
Round-trip
1 adult, Economy
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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 August or September, booked 35 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 March 12, 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 March 12, 2026.
This American Airlines deal was found by Cheapflights users on 3/9. 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.
Fri 4/33:03 pm
BOS
- STL
Nonstop3h 16m
American Airlines
Sat 4/410:33 am
STL
- BOS
1 stop9h 32m
American Airlines
Deal found 3/9![American Airlines logo]()
$342
This American Airlines deal was found by Cheapflights users on 3/9. 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.
Wed 5/63:00 pm
BOS
- STL
Nonstop3h 12m
American Airlines
Mon 5/115:51 am
STL
- BOS
1 stop4h 41m
American Airlines
Deal found 3/9![American Airlines logo]()
$343
This Kiwi.com deal was found by Cheapflights users on 3/7. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/286:00 am
BOS
- STL
1 stop8h 22m
Frontier
Mon 6/14:44 pm
STL
- BOS
2 stops41h 03m
Frontier
Deal found 3/7![Frontier logo]()
$344
This Kiwi.com deal was found by Cheapflights users on 3/8. 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 5/712:35 pm
BOS
- STL
1 stop19h 15m
Frontier
Sun 5/1011:21 am
STL
- BOS
1 stop12h 30m
Frontier
Deal found 3/8![Frontier logo]()
$346
This Kiwi.com deal was found by Cheapflights users on 3/9. 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.
Mon 5/411:16 am
BOS
- STL
1 stop13h 03m
Frontier
Sun 5/104:55 pm
STL
- BOS
2 stops17h 50m
Frontier
Deal found 3/9![Frontier logo]()
$347
This Southwest deal was found by Cheapflights users on 3/9. 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.
Sat 5/96:00 am
BOS
- STL
Nonstop3h 05m
Southwest
Sat 5/92:25 pm
STL
- BOS
2 stops8h 15m
Southwest
Deal found 3/9![Southwest logo]()
$348
This Kiwi.com deal was found by Cheapflights users on 3/11. 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 3/294:23 pm
BOS
- STL
1 stop15h 39m
Multiple Airlines
Mon 3/304:51 pm
STL
- BOS
1 stop27h 42m
Multiple Airlines
Deal found 3/11![Multiple Airlines logo]()
$349
This Southwest deal was found by Cheapflights users on 3/10. 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 5/137:35 am
BOS
- STL
2 stops8h 40m
Southwest
Sat 5/165:35 pm
STL
- BOS
1 stop5h 05m
Southwest
Deal found 3/10![Southwest logo]()
$350
This American Airlines deal was found by Cheapflights users on 3/12. 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.
Thu 5/78:41 am
BOS
- STL
Nonstop3h 13m
American Airlines
Mon 5/115:49 pm
STL
- BOS
Nonstop2h 41m
American Airlines
Deal found 3/12![American Airlines logo]()
$351
This Delta deal was found by Cheapflights users on 3/8. 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.
Wed 4/86:50 pm
BOS
- STL
1 stop6h 08m
Delta
Sat 4/1110:50 am
STL
- BOS
1 stop4h 35m
Delta
Deal found 3/8![Delta logo]()
$353
This Kiwi.com deal was found by Cheapflights users on 3/11. 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.
Mon 3/239:45 am
BOS
- STL
1 stop14h 34m
Multiple Airlines
Tue 3/244:51 pm
STL
- BOS
1 stop23h 03m
Multiple Airlines
Deal found 3/11![Multiple Airlines logo]()
$354
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 March 12, 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 March 12, 2026.
This Southwest deal was found by Cheapflights users on 3/9. 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.
Tue 5/55:45 am
BOS
- STL
Nonstop3h 00m
Southwest
Fri 5/82:30 pm
STL
- BOS
Nonstop2h 35m
Southwest
Deal found 3/9![Southwest logo]()
$352
This Delta deal was found by Cheapflights users on 3/10. 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 5/271:10 pm
BOS
- STL
1 stop5h 06m
Delta
Tue 6/92:18 pm
STL
- BOS
1 stop4h 27m
Delta
Deal found 3/10![Delta logo]()
$373
This United Airlines deal was found by Cheapflights users on 3/9. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/106:25 pm
BOS
- STL
1 stop6h 32m
United Airlines
Sun 4/127:45 am
STL
- BOS
1 stop6h 03m
United Airlines
Deal found 3/9![United Airlines logo]()
$434
This Southwest deal was found by Cheapflights users on 3/10. 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 5/66:20 am
BOS
- STL
2 stops7h 30m
Southwest
Sat 5/92:25 pm
STL
- BOS
2 stops8h 15m
Southwest
Deal found 3/10![Southwest logo]()
$356
This Southwest deal was found by Cheapflights users on 3/11. 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 4/1112:50 pm
BOS
- STL
1 stop7h 45m
Southwest
Sat 4/182:25 pm
STL
- BOS
2 stops8h 15m
Southwest
Deal found 3/11![Southwest logo]()
$358
This Delta deal was found by Cheapflights users on 3/8. 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.
Fri 4/109:00 am
BOS
- STL
1 stop12h 43m
Delta
Sat 4/1110:50 am
STL
- BOS
1 stop4h 35m
Delta
Deal found 3/8![Delta logo]()
$410
This Southwest deal was found by Cheapflights users on 3/8. 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 6/105:50 am
BOS
- STL
Nonstop2h 55m
Southwest
Sun 6/148:00 pm
STL
- BOS
Nonstop2h 30m
Southwest
Deal found 3/8![Southwest logo]()
$379
This Southwest deal was found by Cheapflights users on 3/7. 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.
Sun 5/175:40 am
BOS
- STL
Nonstop3h 00m
Southwest
Tue 5/197:35 am
STL
- BOS
1 stop5h 10m
Southwest
Deal found 3/7![Southwest logo]()
$397
This Southwest deal was found by Cheapflights users on 3/9. 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.
Fri 5/156:45 pm
BOS
- STL
Nonstop3h 10m
Southwest
Sun 5/177:55 pm
STL
- BOS
Nonstop2h 30m
Southwest
Deal found 3/9![Southwest logo]()
$414
This Southwest deal was found by Cheapflights users on 3/11. 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 4/25:15 am
BOS
- STL
Nonstop3h 10m
Southwest
Sun 4/510:20 am
STL
- BOS
Nonstop2h 30m
Southwest
Deal found 3/11![Southwest logo]()
$425
This Southwest deal was found by Cheapflights users on 3/9. 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 8/95:30 am
BOS
- STL
Nonstop2h 50m
Southwest
Sat 8/1511:40 am
STL
- BOS
Nonstop2h 35m
Southwest
Deal found 3/9![Southwest logo]()
$441
This Southwest deal was found by Cheapflights users on 3/9. 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.
Fri 7/246:50 pm
BOS
- STL
Nonstop3h 05m
Southwest
Thu 7/302:30 pm
STL
- BOS
Nonstop2h 35m
Southwest
Deal found 3/9![Southwest logo]()
$441
Last-minute flights from Boston to St. CharlesDiscover last-minute flight deals from Boston to St. Charles. Data last updated March 12, 2026 and is based on user searches.
Discover last-minute flight deals from Boston to St. Charles. Data last updated March 12, 2026 and is based on user searches.
This Kiwi.com deal was found by Cheapflights users on 3/7. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 3/2312:35 pm
BOS
- STL
1 stop22h 57m
Frontier
Mon 3/308:12 pm
STL
- BOS
2 stops14h 29m
Frontier
Deal found 3/7![Frontier logo]()
$351
This Kiwi.com deal was found by Cheapflights users on 3/11. 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.
Mon 3/239:45 am
BOS
- STL
1 stop14h 34m
Multiple Airlines
Tue 3/244:51 pm
STL
- BOS
1 stop23h 03m
Multiple Airlines
Deal found 3/11![Multiple Airlines logo]()
$354
This Kiwi.com deal was found by Cheapflights users on 3/9. 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.
Tue 3/2412:36 pm
BOS
- STL
2 stops22h 13m
Frontier
Sun 3/2911:21 am
STL
- BOS
1 stop23h 20m
Frontier
Deal found 3/9![Frontier logo]()
$357
This Kiwi.com deal was found by Cheapflights users on 3/11. 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 3/294:23 pm
BOS
- STL
1 stop15h 39m
Multiple Airlines
Mon 3/304:51 pm
STL
- BOS
1 stop27h 42m
Multiple Airlines
Deal found 3/11![Multiple Airlines logo]()
$349
This Kiwi.com deal was found by Cheapflights users on 3/11. 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 4/112:42 pm
BOS
- STL
1 stop29h 52m
Frontier
Sun 4/511:21 am
STL
- BOS
1 stop23h 24m
Frontier
Deal found 3/11![Frontier logo]()
$350
This American Airlines deal was found by Cheapflights users on 3/9. 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.
Fri 4/33:03 pm
BOS
- STL
Nonstop3h 16m
American Airlines
Sat 4/410:33 am
STL
- BOS
1 stop9h 32m
American Airlines
Deal found 3/9![American Airlines logo]()
$342
This Delta deal was found by Cheapflights users on 3/8. 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.
Wed 4/86:50 pm
BOS
- STL
1 stop6h 08m
Delta
Sat 4/1110:50 am
STL
- BOS
1 stop4h 35m
Delta
Deal found 3/8![Delta logo]()
$353
This Kiwi.com deal was found by Cheapflights users on 3/10. 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 4/104:23 pm
BOS
- STL
1 stop8h 35m
Multiple Airlines
Mon 4/134:59 pm
STL
- BOS
1 stop16h 22m
Multiple Airlines
Deal found 3/10![Multiple Airlines logo]()
$355
This American Airlines deal was found by Cheapflights users on 3/8. 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.
Thu 4/166:30 am
BOS
- STL
1 stop6h 17m
American Airlines
Mon 4/205:49 pm
STL
- BOS
Nonstop2h 41m
American Airlines
Deal found 3/8![American Airlines logo]()
$343
This Southwest deal was found by Cheapflights users on 3/7. 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.
Thu 4/2311:35 am
BOS
- STL
Nonstop2h 55m
Southwest
Tue 4/282:30 pm
STL
- BOS
2 stops7h 10m
Southwest
Deal found 3/7![Southwest logo]()
$348
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 March 12, 2026.
Search for one-way flight options from Boston to St. Charles. Find affordable one-way fares based on user searches. Data last updated March 12, 2026.
This Kiwi.com deal was found by Cheapflights users on 3/11. 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 4/112:42 pm
BOS
- STL
1 stop29h 52m
Frontier
Deal found 3/11![Frontier logo]()
$84
This Frontier deal was found by Cheapflights users on 3/8. 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.
Tue 5/511:16 am
BOS
- STL
1 stop13h 03m
Frontier
Deal found 3/8![Frontier logo]()
$96
This Frontier deal was found by Cheapflights users on 3/9. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 4/125:30 am
BOS
- STL
1 stop6h 08m
Frontier
Deal found 3/9![Frontier logo]()
$100
This Kiwi.com deal was found by Cheapflights users on 3/10. 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.
Mon 5/118:44 am
BOS
- STL
2 stops49h 11m
Frontier
Deal found 3/10![Frontier logo]()
$101
This Frontier deal was found by Cheapflights users on 3/10. 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 5/811:16 am
BOS
- STL
1 stop13h 03m
Frontier
Deal found 3/10![Frontier logo]()
$106
This Frontier deal was found by Cheapflights users on 3/9. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 6/96:00 am
BOS
- STL
1 stop8h 22m
Frontier
Deal found 3/9![Frontier logo]()
$111
This Expedia deal was found by Cheapflights users on 3/8. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 4/211:26 am
BOS
- STL
1 stop21h 02m
Frontier
Deal found 3/8![Frontier logo]()
$115
This Frontier deal was found by Cheapflights users on 3/9. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 4/911:26 am
BOS
- STL
1 stop12h 59m
Frontier
Deal found 3/9![Frontier logo]()
$117
This Kiwi.com deal was found by Cheapflights users on 3/8. 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 3/3112:36 pm
BOS
- STL
2 stops11h 43m
Frontier
Deal found 3/8![Frontier logo]()
$122
This Kiwi.com deal was found by Cheapflights users on 3/10. 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 5/1911:16 am
BOS
- STL
2 stops22h 39m
Frontier
Deal found 3/10![Frontier logo]()
$124
This Kiwi.com deal was found by Cheapflights users on 3/9. 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.
Wed 4/86:01 am
BOS
- STL
2 stops36h 33m
Multiple Airlines
Deal found 3/9![Multiple Airlines logo]()
$125
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 March 12, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $342 (American Airlines) |
One-way from | $84 (Kiwi.com) |
Popular in | April |
Cheapest in | August |
Average price | $506 |
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 March 12, 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
Tue 5/5
5:45 am-7:45 am
Nonstop3h 00m
Lambert-St Louis
Fri 5/8
2:30 pm-6:05 pm
Nonstop2h 35m
$352
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Wed 5/6
6:20 am-12:50 pm
2 stops7h 30m
Lambert-St Louis
Sat 5/9
2:25 pm-11:40 pm
2 stops8h 15m
$356
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Sat 4/11
12:50 pm-7:35 pm
1 stop7h 45m
Lambert-St Louis
Sat 4/18
2:25 pm-11:40 pm
2 stops8h 15m
$358
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Wed 5/27
1:10 pm-5:16 pm
1 stop5h 06m
Lambert-St Louis
Tue 6/9
2:18 pm-7:45 pm
1 stop4h 27m
$373
Quickest round-trip
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Wed 6/10
5:50 am-7:45 am
Nonstop2h 55m
Lambert-St Louis
Sun 6/14
8:00 pm-11:30 pm
Nonstop2h 30m
$379
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Sun 5/17
5:40 am-7:40 am
Nonstop3h 00m
Lambert-St Louis
Tue 5/19
7:35 am-1:45 pm
1 stop5h 10m
$397
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Fri 4/10
9:00 am-8:43 pm
1 stop12h 43m
Lambert-St Louis
Sat 4/11
10:50 am-4:25 pm
1 stop4h 35m
$410
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Fri 5/15
6:45 pm-8:55 pm
Nonstop3h 10m
Lambert-St Louis
Sun 5/17
7:55 pm-11:25 pm
Nonstop2h 30m
$414
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Thu 4/2
5:15 am-7:25 am
Nonstop3h 10m
Lambert-St Louis
Sun 4/5
10:20 am-1:50 pm
Nonstop2h 30m
$425
BostonSt. Louis
BOS - STL
BOSSTL
Boston Logan Intl
Fri 4/10
6:25 pm-11:57 pm
1 stop6h 32m
Lambert-St Louis
Sun 4/12
7:45 am-2:48 pm
1 stop6h 03m
$434
Showing 1-10 of 21 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
How far ahead should I book a flight from Boston to St. Charles?
Use this chart to determine the optimal time to book a round-trip flight from Boston to St. Charles. Price data was last updated on March 6, 2026.
To ensure you get the cheapest price possible for a flight from Boston to St. Charles, you should look to book at least 35 days in advance of your intended travel date. The price of your flight may increase if you delay and leave booking until a week or so before departure.
What is the cheapest month to book a flight from Boston to St. Charles?
Currently, August is the cheapest month in which you can book a flight from Boston to St. Charles (average of $179). Flying from Boston to St. Charles in February is currently the most expensive (average of $299). 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 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 March 12, 2026.
It’s optimal to fly from Boston to St. Charles in the evening. By choosing this option you can save up to 9% on the cost of your flight, compared to a flight at noon.
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 March 12, 2026.
Travelers seeking maximum savings on their Boston to St. Charles flight should consider departing on Monday evenings when fares are most often at their lowest. Tuesday 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 March 12, 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.
Comfort
8.0
Food
7.0
Entertainment
7.5
Boarding
8.1
Crew
8.6
Overall
8.0
Reviews
1 / 20
10.0
ExcellentAnonymous,Mar 2026
KOA - HNL
Comfort
8.0
Food
7.0
Entertainment
7.5
Boarding
8.1
Crew
8.6
Overall
8.0
Reviews
1 / 20
10.0
ExcellentAnonymous,Mar 2026
KOA - HNL
Comfort
8.0
Food
7.0
Entertainment
7.5
Boarding
8.1
Crew
8.6
Overall
8.0
Reviews
1 / 20
10.0
ExcellentAnonymous,Mar 2026
KOA - HNL
Comfort
8.0
Food
7.0
Entertainment
7.5
Boarding
8.1
Crew
8.6
Overall
8.0
Reviews
1 / 20
10.0
ExcellentAnonymous,Mar 2026
KOA - HNL
Comfort
8.0
Food
7.0
Entertainment
7.5
Boarding
8.1
Crew
8.6
Overall
8.0
Reviews
1 / 20
10.0
ExcellentAnonymous,Mar 2026
KOA - HNL
Comfort
8.0
Food
7.0
Entertainment
7.5
Boarding
8.1
Crew
8.6
Overall
8.0
Reviews
1 / 20
10.0
ExcellentAnonymous,Mar 2026
KOA - HNL
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.
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Alternative routes for Boston to St. Charles
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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
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Boston and St. Charles flights
Browse other Boston and St. Charles flight options. Last updated on March 12, 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 March 12, 2026.
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Boston to St. Charles flights
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Top 7 airlines flying from Boston to St. Charles
Discover the top 7 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 March 12, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$63 | Average$207 | FlexibilityNo cancel fee | On-time65% | |
| Cheapest$90 | Average$270 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$148 | Average$368 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$285 | Average$517 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$292 | Average$409 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$318 | Average$477 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$327 | Average$430 | FlexibilityNo cancel fee | On-time62% |