$99 Find Cheap Flights from Boston to St. Charles

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Boston to St. Charles departing on 4/5. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
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Everything you should know

Cheapest round-trip
$344
Typical prices: $581-$419
Multiple Airlines
Sat 4/18Mon 4/20
BOS - STL • 2 stops
Cheapest non-stop
$350
Typical prices: $576-$407
American Airlines
Tue 5/19Sat 5/23
BOS - STL • Non-stop
Arrival airport
You can't fly directly to St. Charles. It is served by St. Louis (STL), located 7.2 miles from St. Charles.
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Flight Deals
Useful Info
Flight Deals

Cheap Flights from Boston to St. Charles (BOS-STL)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Boston to St. Charles that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Boston to St. Charles

Sat, Apr 18 - Mon, Apr 20
Multiple Airlines Logo
10:26 pm - 6:50 am
BOS
-
STL
33h 24m
2 stops
Multiple Airlines Logo
8:23 pm - 11:45 am
STL
-
BOS
14h 22m
1 stop
$344Multiple Airlines
Wed, May 6 - Sat, May 9
Southwest Logo
5:55 pm - 8:00 pm
BOS
-
STL
3h 05mnonstop
Southwest Logo
12:30 pm - 11:50 pm
STL
-
BOS
10h 20m
1 stop
$345Southwest
Wed, May 6 - Sat, May 9
Southwest Logo
2:25 pm - 10:00 pm
BOS
-
STL
8h 35m
2 stops
Southwest Logo
6:20 am - 1:35 pm
STL
-
BOS
6h 15m
1 stop
$346Southwest
Thu, May 14 - Sun, May 17
Frontier Logo
10:07 am - 12:21 am
BOS
-
STL
15h 14m
1 stop
Frontier Logo
4:19 pm - 9:12 am
STL
-
BOS
15h 53m
1 stop
$347Frontier
Thu, Apr 23 - Mon, Apr 27
Frontier Logo
6:00 am - 6:50 am
BOS
-
STL
25h 50m
1 stop
Frontier Logo
8:23 pm - 11:57 am
STL
-
BOS
14h 34m
1 stop
$348Frontier
Sun, Apr 26 - Tue, Apr 28
Multiple Airlines Logo
10:25 am - 11:19 pm
BOS
-
STL
13h 54m
1 stop
Multiple Airlines Logo
4:59 pm - 1:31 am
STL
-
BOS
31h 32m
2 stops
$349Multiple Airlines
Sat, May 2 - Wed, May 6
American Airlines Logo
8:00 am - 12:35 pm
BOS
-
STL
5h 35m
1 stop
American Airlines Logo
5:49 pm - 9:30 pm
STL
-
BOS
2h 41mnonstop
$350American Airlines
Tue, Apr 7 - Thu, Apr 9
Multiple Airlines Logo
4:23 pm - 11:25 pm
BOS
-
STL
8h 02m
1 stop
Multiple Airlines Logo
6:29 pm - 11:59 pm
STL
-
BOS
28h 30m
2 stops
$351Multiple Airlines
Wed, May 6 - Sat, May 9
Southwest Logo
2:25 pm - 10:00 pm
BOS
-
STL
8h 35m
2 stops
Southwest Logo
5:40 am - 3:10 pm
STL
-
BOS
8h 30m
2 stops
$352Southwest
Thu, May 7 - Sat, May 9
American Airlines Logo
3:00 pm - 5:12 pm
BOS
-
STL
3h 12mnonstop
American Airlines Logo
5:54 pm - 9:35 pm
STL
-
BOS
2h 41mnonstop
$353American Airlines
Useful Info

Good to know

Low seasonJanuary
Cheapest flight$99
Best time to beat the crowds with an average 11% drop in price.
Most popular time to fly with an average 11% increase in price.
Flight from Boston to St. Louis

When to book flights from Boston to St. Charles

Are your dates flexible? Find out the best times to travel from Boston to St. Charles based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price

FAQs for booking flights from Boston to St. Charles

  • Which airports will I be using when flying from Boston to St. Charles?

    When flying out of Boston you’ll be using Boston Logan Intl. St. Charles does not have its own airport so you’ll be flying into nearby Lambert-St Louis airport, which is 7.2 mi away.

  • How long does a flight from Boston to St. Charles take?

    Direct flights cover the 1,043 miles separating Boston and St. Charles in about 2h 55m.

  • How many flights are there between Boston and St. Charles?

    8 direct flights run between Boston and St. Charles on a daily basis. On average, there are about 62 departures each week.

  • What’s the cheapest day of the week to fly between Boston and St. Charles?

    Consider leaving on a Friday and avoid Saturdays if you are looking for the best rates. For your return to Boston, you’ll find the best rates on Wednesdays and the most expensive ones on Saturdays.

  • How does KAYAK find such low prices on flights from Boston to St. Charles?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Boston to St. Charles.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Boston to St. Charles?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to St. Charles from Boston is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Boston to St. Charles?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to St. Charles with an airline and back to Boston with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Boston to St. Charles?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to St. Charles from Boston up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

  • Which airlines provide the cheapest flights from Boston to St. Charles?

    In the last 72 hours, the cheapest one-way ticket between Boston and St. Charles found on KAYAK was with Frontier for $80. Spirit Airlines offered a round-trip connection from $63 and Frontier from $90.

Top tips for finding cheap flights from Boston to St. Charles

  • There is no airport in St. Charles. Instead, you’ll be flying into St. Louis Lambert Airport when flying between Boston and St. Charles.
  • The cheapest flight from Boston to St. Charles was found 35 days before departure, on average.
  • Book at least 3 weeks before departure in order to get a below-average price.
  • High season is considered to be February, March and April. The cheapest month to fly is August.

Reviews of the top 5 airlines serving Boston to St. Charles

 
Need help choosing which airline to fly with from Boston to St. Charles? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
8.0
SouthwestOverall score based on 4333 reviews
7.5Entertainment
8.1Boarding
8.0Comfort
8.6Crew
7.0Food
Airline reviews

Great flight. Good snacks and drinks. Grateful it was free. The flight from Nashville to louisville, i think her name was Tracy (not sure that's right) super awesome, nice and cheerful. She really enjoyed being at work today! She was the person who scanned the boarding pass on flight wn941. She should be recommended for a raise !

10.0 ExcellentGwen, Mar 2026
DAL - BNA
Read more Southwest reviews

Great flight. Good snacks and drinks. Grateful it was free. The flight from Nashville to louisville, i think her name was Tracy (not sure that's right) super awesome, nice and cheerful. She really enjoyed being at work today! She was the person who scanned the boarding pass on flight wn941. She should be recommended for a raise !

I liked it better when you were truer to your roots Am paying more for less fun

Southwest was greaat! The most expensive but the least upsetting for those we were flying to see.

I flew twice this week on Southwest, was delayed over 2 hours both ways. From Pittsburgh to Chicago it was due to weather but the gate agents, pilot etc were great at updating everyone. Today from Midway to Pittsburgh the plane had come from an international location, kept getting delayed, no information was given until we were delayed for the third time. It was ridiculous, whoever scheduled that plane to fly to Pittsburgh after didn’t consider a lot of things.

Boarding was easy. The seats are small and fairly uncomfortable

I was supposed to be on a later flight. When I showed up at the gate, the woman working there was extremely helpful getting moved up to this earlier flight.

We had a 5 hour delay on the tarmac in Baltimore

Long layover between flights to Long Island from BWI - need better coordination between flights

I elected to pay for the upgrades and found very little difference

The new seating arrangement is so over priced for what you get.

Snacks and included beverages were appreciated. Boarding went smoothly. Plenty of overhead bin space. Seats get very uncomfortable after a couple of hours. After waiting 10 painful minutes for my walker, a very nice Delta guest agent pushed me in a wheelchair to the gate. It was finally delivered to me after another 15 minutes . Our checked bag was on the carousel long b4 I was able to retrieve it. Fortunately it was still there but somewhere along the way the straps we used to secure it were removed and and were not reattached. Wish I had made note of the agents name.

It was fine. 55 minute flight. No snacks or beverage service offered. Boarding went smoothly and my walker was waiting for me on the jet way.

Smaller plane for a longer flight than my first one. Doesn’t make sense.

The cabin temperature was nice and cool. The wifi was not working.

Flight late, the waited for a long time for “personal” to arrive at gate to dock the plane in Rochester. So annoying. This flight was expected, why aren’t personel available for the jet bridge?

As previously noted, this flight was great: departure was timely, the crew was friendly and attentive, and wifi connectivity was seamless. In particular, I appreciated that the flight attendant just told me to stow the laptop right before takeoff/landing, and trusted me to do so (which I did!).

Kayak botched up the booking, i had to call delta and fix. In the process Delta failed to honor my comfort plus seat assignment that i had previously.

Entertainment is ok! Boarding and seat with zone is terrible. I paid for the seats but you didn’t give me what I paid for which is exit isles.

the crew cancel the morning service due to the weather. Then the flight got deverted to Nashville . we were on the ground for over two hours the only gave us water once... no food or any snacks.... the crew should have handled better and offered something to passengers.

My recent experience was excellent on Delta! I flew with Delta Comfort and I was really comfortable in my seat. I enjoyed the in-flight service. The flight attendants were so friendly and hospitable. I love the snack on the flight as well. This was my first time flying on Delta and I will definitely consider flying with them again.

Onboard functioning wide-variety entertainment on a budget and having an open pantry is nice. Seats are not comfortable but go provide plenty of legroom for a 6'2" 260lbs man.

Even though the weather made a lot of flights become cancelled Jet Blue made the flight that was supposed to leave at 9 pm and we left at 12:15 am and I was so grateful- Thanks to the Senior Jet Blue Staff who made those decisions

Worst customer service ever experienced on the planet, dirty plane, no communication, and severe delays

Flight cancelled 2 hours prior to boarding. No explanation. No refunds.

Delayed by 1.5 hours. Terrible apologies, half hearted at best. It will be a LONG time until i book w Jet Blue again. Very disappointed.

My check in was stressful. I somehow lost my seat from my original booking, the plane showed no availability/no seat when it was time to check-in. I called and was instructed to try to get a seat at the airport. I asked if it was a full flight and the travel agent said the site showed some seating but was not able to secure one for me. Why not? On my way to the airport the app finally revealed one available seat towards the back of the aircraft that I was able to book. It ended up being an overbooked flight, so glad I wasn't stuck.

Flights with JetBlue from San Diego to Boston are a miserable experience. The flight was delayed about 1.5 hours due to “weather” supposedly but the flights for other airlines left on time so it just have been some kind of weather that only affects JetBlue. I had a small carry on - purse. The crew stored it in a bin 2 rows down from me because they were using the bin next to my seat for other people’s stuff. The TV screen in the emergency row seats does not work. It just was awful from start to finish. When we landed, we had to sit inside the plane for a very long time because the plane had to be moved to a different gate.

They made me check my bag and I didn't need to as there was overhead space available. I paid for a seat towards the front of the plane and it didn't recline. I requested a refund and they declined to give me one.

I have to congratulate Kayak (and Dylan the Chatdeal agent) because because when we decided extended our trip in Florida by two days, there were many direct flights oprions back to Boston available on the Friday we wanted to fly on the JetBlue website, but once I canceled the original JetBlue flight on their website, those direct return options disappeared immediatley! I think it's a game JetBlue plays. . Luckily, I checked Kayak and they had a direct flight that wasn't appearing on JetBlue's website and so I booked it, and we were able to fly home direct through the Kayak booking when JetBlue was offering nothing (even though I have been a True Blue member for 20 years, and also am a Mosaic member). So much for loyalty- their algorithm for booking is like a shell game. JetBlue used to be a good company but now they're worse than anyone. Also I was originally booked this trip to Florida, two months before the departure date, I booked the trip on JetBlue's website and then after the payment part, they said there was a problem and that I needed to do the booking again, so when I immediately went to rebook , the price had gone up 30%! I called them and it sounded like they had heard this so many times before and the guy told me to check back in 10 minutes and the price would be back to where it was when I was booking- it but it never was. How could the price go up 30% in one minute two months before the flight???? They're playing a game with their customers. Anyways, I booked a cheaper flight then at a less convenient time. So fast forward two months the night before the 7 AM flight, they sent me an email at midnight when I was sleeping to let me know that my flight at 7 AM had been canceled. The only thing they offered was a flight that night from from a different airport (Providence) to a different airport in Florida (West Palm Beach) or a flight two days later. No compensation, nothing. They couldn't of tried to get another plane to the Boston airport? They had all night to do it. I passed on their ridiculous options and flew with Delta and it was a great experience. Of course, I had to pay a lot more booking on the same day, but JetBlue doesn't care. I put in a lengthy complaint with the agent who assured me someone would get back to me by email within three days and I haven't heard a thing. JetBlue used to be a good company but now they're among the worst. The only thing they still have is decent legroom, but the corporate bean counters will probably start taking that away too.

We were made to wait in the airport for six hours for a flight that was ultimately canceled.

Delays with no explanation. It could have been handled better.

Ceiling fell down and had to have maintenance come and duct tape it up. No WiFi on the flight.

A first class seat should fit a fat person, and this doesn't. The trays in the armrest are less functional than an ordinary tray in the back of the seat.

The flight attendant was friendly and efficient. The temperature was kept nice and cool. The plane was nice, but filthy. There were visible spills on my tray table. The gate agent was somewhat rude with her announcements and in speaking with other customers.

I appreciate that I finally got the seat I paid extra for this time. Thank you

I would have liked vegetarian and gluten free options for evening dinner time flight. I would have like a pillow on the international overnight flight . The veg wrap and oaten desert on the international flight was good

The experience at checkin for my American Airlines flight from Sacramento to LAX was very good including the assistance I received in getting my bags checked in and boarding passes printed. Was pleasantly surprised the my bags were checked through all the way to my destination at Clark International Airport in Angeles, Philippines.

Absolutely terrible. Would never fly American again. 2 deplaned incidents and delayed by close to 24 hours. $12 meal voucher for first class passengers was an insult to the injury. Pathetic.

Terrible planning. And even worse gate agents. Absolutely rude behavior.

Half of the TSA checkpoints at PHL are closed. Also, there is no standby for first class passengers. You can only standby for coach. Very dated policy and inconsistent with peers.

The crew acted like they had never done this and kept barking passive aggressive orders at people. + the security line + the delay + sitting on the tarmac for 2 hours + none of the apps or signage updating with correct times

More inflight connection. And leg space is horrible. And the paying for baggage I'd ridiculous!!!

My flight was originally from SAT to MCO connecting from MCO to ORD. We got diverted to ATL and than Frontier staff there was sooo un helpful first they said they couldn’t give us any accommodation since our flight first got delayed that cancelled and now it’s 221am and I am still in ATL since they said they need to create a new flight my final destination is ORD and I have been delayed twice and cancelled. With no real help the frontier app didn’t work no email updates over all such a horrible experience

There's no seats that lean back with little leg space i wad uncomfortable the entire flight. Your charges for extra baggage is despicable and costly!!

Remind customers of the need to have passport or new ID for boarding.

Flight was canceled. Most upsetting was message from Kayak, stating that the flight was canceled and click with Kayak for details regarding rebook, refund details. THERE'S NO INFORMATION PROVIDED BY KAYAK EXCEPT THAT FLIGHT IS CANCELED. AND NOW THIS SURVEY TO FIND OUT HOW WAS THE FLIGHT !!!!!!!

The flight never took off and we spent 7 hours at the airport

Gate not determined until I got to the airport - hard to plan the trip to the airport.

Our flight was canceled. I will never use Kayak nor Frontier for travel again. The entire experience was a headache.

Frontier.. nickel and dime add-ons. Flight late, on time, late again, last minute gate change, arrival gate required a shuttle to the terminal. They sure keep you guessing.. if you like a little chaos and airport anxiety, this is the airline for you!

Everything you need to know for your flight from Boston to St. Charles

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