$124 Find Cheap Flights from Boston to St. Charles - Compare and Save

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 9/5. 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.
1 adult
1 adult, Economy, 0 bags

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Everything you should know

Cheapest round-trip
$339
Typical prices: $391-$652
Frontier
Tue 10/6Wed 10/21
BOS - STL • 1 stop
Cheapest non-stop
$343
Typical prices: $358-$610
American Airlines
Thu 9/3Sun 9/6
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
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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

Tue, Oct 6 - Wed, Oct 21
Frontier Logo
12:52 pm - 1:10 pmBOS  Boston Logan Intl-STL Lambert-St Louis
25h 18m1 stop Atlanta Hartsfield-Jackson
Frontier Logo
10:35 am - 10:52 amSTL  Lambert-St Louis-BOS Boston Logan Intl
23h 17m1 stop Atlanta Hartsfield-Jackson
$339Frontier
Thu, Oct 8 - Tue, Oct 20
Frontier Logo
11:28 am - 9:40 amBOS  Boston Logan Intl-STL Lambert-St Louis
23h 12m1 stop Atlanta Hartsfield-Jackson
Frontier Logo
10:35 am - 10:52 amSTL  Lambert-St Louis-BOS Boston Logan Intl
23h 17m1 stop Atlanta Hartsfield-Jackson
$339Frontier
Wed, Sep 23 - Sat, Sep 26
Southwest Logo
5:35 am - 7:25 amBOS  Boston Logan Intl-STL Lambert-St Louis
2h 50mnonstop
Southwest Logo
3:00 pm - 9:45 pmSTL  Lambert-St Louis-BOS Boston Logan Intl
5h 45m1 stop Baltimore/Washington
$340Southwest
Sat, Sep 5 - Wed, Sep 9
American Airlines Logo
4:59 pm - 7:07 pmBOS  Boston Logan Intl-STL Lambert-St Louis
3h 08mnonstop
American Airlines Logo
11:01 am - 9:00 pmSTL  Lambert-St Louis-BOS Boston Logan Intl
8h 59m1 stop Chicago O'Hare Intl
$342American Airlines
Sat, Sep 5 - Wed, Sep 9
American Airlines Logo
11:58 am - 4:43 pmBOS  Boston Logan Intl-STL Lambert-St Louis
5h 45m1 stop Chicago O'Hare Intl
American Airlines Logo
11:01 am - 9:00 pmSTL  Lambert-St Louis-BOS Boston Logan Intl
8h 59m1 stop Chicago O'Hare Intl
$342American Airlines
Sat, Sep 5 - Sun, Sep 6
Southwest Logo
5:50 am - 12:35 pmBOS  Boston Logan Intl-STL Lambert-St Louis
7h 45m2 stops Baltimore/Washington Atlanta Hartsfield-Jackson
Southwest Logo
2:45 pm - 10:30 pmSTL  Lambert-St Louis-BOS Boston Logan Intl
6h 45m1 stop Nashville Intl
$342Southwest
Thu, Oct 29 - Sun, Nov 1
Multiple Airlines Logo
12:35 pm - 9:40 amBOS  Boston Logan Intl-STL Lambert-St Louis
22h 05m1 stop Atlanta Hartsfield-Jackson
Multiple Airlines Logo
10:35 am - 10:09 amSTL  Lambert-St Louis-BOS Boston Logan Intl
22h 34m2 stops Atlanta Hartsfield-Jackson Fort Lauderdale
$354Multiple Airlines
Wed, Dec 16 - Fri, Dec 25
Delta Logo
9:05 am - 1:26 pmBOS  Boston Logan Intl-STL Lambert-St Louis
5h 21m1 stop Atlanta Hartsfield-Jackson
Delta Logo
11:51 am - 7:21 pmSTL  Lambert-St Louis-BOS Boston Logan Intl
6h 30m1 stop Atlanta Hartsfield-Jackson
$363Delta
Sat, Sep 5 - Mon, Sep 7
Delta Logo
6:50 am - 11:56 amBOS  Boston Logan Intl-STL Lambert-St Louis
6h 06m1 stop Atlanta Hartsfield-Jackson
Delta Logo
5:23 pm - 1:25 amSTL  Lambert-St Louis-BOS Boston Logan Intl
7h 02m1 stop Atlanta Hartsfield-Jackson
$363Delta
Sat, Oct 10 - Mon, Oct 12
Multiple Airlines Logo
10:19 am - 9:40 amBOS  Boston Logan Intl-STL Lambert-St Louis
24h 21m2 stops Fort Lauderdale Atlanta Hartsfield-Jackson
Multiple Airlines Logo
8:34 pm - 10:09 amSTL  Lambert-St Louis-BOS Boston Logan Intl
12h 35m1 stop Orlando
$366Multiple Airlines
Useful Info

Good to know

Low season

February

Cheapest flight

$124
Best time to beat the crowds with an average 5% drop in price.
Most popular time to fly with an average 3% 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 50m.

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

    10 direct flights run between Boston and St. Charles on a daily basis. On average, there are about 73 departures each week.

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

    Consider leaving on a Tuesday and avoid Saturdays if you are looking for the best rates. For your return to Boston, you’ll find the best rates on Tuesdays 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 5 days, the cheapest one-way ticket between Boston and St. Charles found on KAYAK was with Frontier for $67. Frontier offered a round-trip connection from $90 and Delta from $148.

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 51 days before departure, on average.
  • Book at least 2 weeks before departure in order to get a below-average price.
  • High season is considered to be June, July and August. The cheapest month to fly is January.

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 4214 reviews
8.6Crew
8.0Comfort
7.0Food
7.5Entertainment
8.1Boarding
Airline reviews

Just crazy with times being pushed and pushed and pushed and gate crew at Philly super rude and unprofessional with many under stress with delays.

2.0 MediocreHans, Aug 2026
Read more Southwest reviews

Just crazy with times being pushed and pushed and pushed and gate crew at Philly super rude and unprofessional with many under stress with delays.

Great job! My family doesnt fly often but we felt safe 100%

Communication about the delayed flight was poor. We were told to move gates three times but that was bad information. We went from gate 128 to gate 126 and then to gate 123 and back to gate 126. Communication about the delay was bad. Ended up being 1 1/2 hour late getting home.

I have roller bag with food and medication told me I couldn't bring on my 2nd flight today. 15 years flying with SW never an issue with that bag.

WiFi was not working and didn’t have a beverage service

I have not flown Southwest in awhile and had a very pleasant experience. From ticketing to boarding to the flight. The flight left on time and landed ahead of schedule. It won't be so long next time!!

Everything went smoothly and we even arrived a little bit early.

Great flight. Outstanding Service. Southwest was able to put us on a direct flight to Denver when the connection could have been affected by a later arrival to Baltimore. The direct flight was less expensive that the flight with the connection in Baltimore.

Boarded on time but once we were ready for take off, the crew determined that, although every seat was taken, somehow someone was on the wrong flight. Delay, delay delay, announcements and ended up with one person checking EVERY ID against their passenger Manifest only to figure out it was a "clerical error." We departed 54 minutes late causing me to run in the St. Louis Airport to make my connection and lose the priority boarding spot I had paid for. Unnecessary delay.

Flights delayed by 4-6 hours. Boarding was a mess and unclear. Bags were not at arrival airport and had never even been put on the plane. No idea when I’ll get them. Don’t fly into Denver!

Stewardess was not accommodating when I requested a second drink.

Although I know the Airlines cannot control the situation when there’s a ground stoppage, it would’ve been nicer if we would have had more up-to-date information clarity around the delays. Additionally, I think the delays also took a toll on the Cabin crew, particularly the lead flight attendant in first class. She was not very friendly when we boarded the plane for many of the passengers. Number one she refused to hang a garment bag in the front closet for a first class passenger, she was unwilling to dispose of an empty bottle in the trash as I was boarding (despite drinking a bottle of water herself and needing to disregard), and she was very combative with a passenger, who needed to access something from his bag that was Gate checked. Frankly, it was really unfortunate as I’ve never seen a flight attendant behave that way directly to the passengers, particularly when none of us had done anything wrong.

Flight from Savannah arrived very late and we did not take off till 2 hours after scheduled departure!

It is usually very pleasant. Good service for the price, international flights are even better

Flight attendant was very poor in taking care or showing attention. I slept up front for a few and missed the snacks. She saw me many times, went by me many times and never once asked if I needed anything. The whole 2 hours flight. And this is to a Diamond member in first.

I thought the service was very nice and pleasant. There were no hiccups and no issues so overall a good experience.

It was a pleasant surprise to have complimentary Wi-Fi on the flight

Flight was delayed, we could have been notified earlier and in a consistent manner. App was not refreshing for another passenger to get the latest flight status. We could have stayed and waited at the hotel instead of waiting at the airport had we known the flight was going to delayed for more than 5 hours. The toilet is too tight, and needs to be cleaned more frequently (every hour). The entertainment screen froze, the touch screen not responding to touch. We were upgraded to comfort, it is more comfortable than regular economy seats.

The baggage belt was not updated on the Delta App and was displayed on the wrong belt board. Was not expecting this to happen.

The plan was delayed and left DC 90 minutes late. However, it showed a 20 minute delay on the delta app, then a 12 min delay. It turned out to be an hour delay. I found out where the plane was with flightaware. Stop keeping customers in the dark about what is going on.

The flight was delayed in 30 minute increments for a total of 4 hours and 30 minute delay. All other flights to Chicago left on time except for this one flight. If there is an issue with the inbound flight, just let customers know so they can find another flight right away, Once we got on the plane there was another 30 minute delay taking off at 10:30 at night which is very unusual that a flight wouldn't be ready to take off

They have overselled the ticket and kicked me out from boarding, All my Plans were collapsed and important network meeting missed.also I booked direct flight i have to go through an 1 stop and it was frustrated.

Horrific. We were delayed due a flight attendant stuck in traffic en route to the airport. Over 100 people were then stuck in Charolette. Then I ran to make my layover only to find that my connection didn’t have a plane anymore. Waited 2.5 hours without any updates. On the flight we had to beg for even a pretzel option.

Terrible boarding and first class experience. Nice staff but overall disorganized, dirty plane.

The flight was delayed significantly and we sat on runway after landing for awhile. Best thing was the flight attendant, Jenny, in first class, who was very professional and attentive. She was excellent - the rest of the flight was not.

Early departure meant on time arrival. Only real problem was free internet had issues, although chatting with the internet help desk (you can do this via aainflight.com) got the issue resolved.

The staff and service on American Airlines were truly outstanding. I had requested wheelchair assistance for my mother due to her knee issues, and the team went above and beyond every step of the way—from boarding in Boston to our arrival in Chicago. Their care, professionalism, and attentiveness made the entire experience smooth and stress-free. I’m very grateful for the support they provided.

Found that the plane used for this short flight is smaller and therefore the seats are really squeezed tight.

Great experience. Good dinner and service. FA's were very nice and attentive.

I like the speed of boarding and deplaning and the fact that everything was on time. The crew (attendants) were probably quite new and did not begin the in cabin service until 30 min before landing even though there was little to no air turbulence for the last 1.5 hours of the flight. It made for a mad scramble at the end to get trash collected and carts stowed before touch down.

JetBlue cancelled the flight along with hundreds of others, for no apparent reason. no recourse, no rebooking options. never booking with them again

Jet Blue cancelled my flight after I had boarded. They attempted to rebook me for a new flight two days later. I was able to rebook with a different airline, but not until the next morning. As such, I was forced to get an expensive hotel and missed important work meetings Monday morning. I am very disappointed with the customer service and will be pursuing full reimbursement for my hotel cost.

Flight delayed 4 times on a non-stop from BOS to SFO. Then when landed in SFO had to wait for 30 mins for a gate AT 3:30AM.

Horrible - for the first time in my life i was denied boarding an international flight because the name used on my ticket - Josh - was not exactly the same as my passport - Joshua. At no time during ticketing, online check-in, or at the airport flying from Boston to NY was i notified of a problem. It was only at boarding from NY to Costa Rica I was informed of the problem and by then it was too late. After missing the flight I was told by airport Jet Blue staff, including a supervisor, that it was my problem and they could not assist because i bought "the cheapest fare". i was hung up on twice by JetBlue customer service, including once by a supervisor. I blame Kayak and your awful partner ChatDeal for even allowing me to purchase an international ticket without verifying this - you effectively sold me a ticket i could not use. Shame on you and shame on ChatDeal for doing nothing to help me resolve the situation. What a scam.

The flight kept getting delayed, but the ground crew did not communicate well to the passengers in the terminal. First, we were told that it was an engine issue. That was understandable. We asked, after the third delay, if it would be canceled; they reassured us that that would not happen because a new plane was on its way from Washington DC. Four hours later, that is exactly what happened. No announcement was made only people who had the JetBlue app learned of the cancellation. They rebooked us on a flight that would get into our destination 36 hours after our original time I had to spend an exorbitant amount of money to book an additional flight with a different airline, the following morning in order to make it to my conference in time. Not to mention the fact that by the time I discovered the cancellation on the departures board, it was too late for me to receive a refund on my lodging in the destination city for that night. Because I had booked with KAYAK, I did not receive any JetBlue email with rebooking information. This is what the information information desk kept telling everyone who inquired about a rebooking. This was my first time flying with JetBlue. Needless to say, after extremely poor communication andover $1000 of additional expense later, I will not be flying with them again.

We were several hours delayed due to confusion during boarding. Evidently the crew could not match the manifest with the boarded customers. After significant time trying to find individuals on board, a crew member walked through the entire plane re-scanning each of our boarding passes. Then we had to wait for a new slot to depart, and when we landed, our gate was not ready. It was a complete goat rodeo from start to finish.

Horrible. Flight was cancelled, jet blue app not working to rebook, no phone number available to call Jet Blue, 400 ish people in line for the help desk, stuck in Boston for 2 more days had to book new flight with a different airline and still not sure if I will be able to get any refund.

Flight left 2 hours late with no explanation as to the delay

Whole experience was poor. Delayed 2 hours. Lied about the delays. Was all jet blues fault and tried to blame on air traffic control. Sent out other let trips and wouldn't allow people to switch aircraft.

My bag was not loaded on my flight. it was not communicated to me until i was waiting for my bag at my destination. there was no confirmation of when my bag was arriving and no way to track it.

I know Frontier is a “no-frills” airline. I understand the concept. However, I jumped on some tickets for our family vacation, expecting to play a bit of a game to figure out the family bags and not over spend. In the end, I got the short end of this deal by far. 1. I did not expect them to charge the baggage fee for each direction. It makes the fee look high-ish at a glance, but reasonable. Then when you get to checkout and realize you have to pay it twice to come home with your luggage, it becomes ridiculous. 2. The low checked bag weight limit. I am used to packing a 50lb bag with my preferred airline. Frontier’s artificially low 40lb limit more quickly triggers the extra weight fee, which almost DOUBLES the price of the bag if you go over ($79 for the bag/$75 for the next 10 lbs) 3. The fee for a carry-on bag is the same as a checked bag but with a lower size and weight limit. Make it make sense! 4. The seats are terrible. My 2.5 hour flight almost had me losing my mind. I’m 6’3” and my femurs barely fit in the space provided. My knees had to wiggle just right to jam into the crack next to the armrest of the seat in front of me. The cushioning was thin and inadequate. I am tall but I’m not a freak. These seats are unacceptable. 5. I overheard the woman next to me speaking with the gate agent about being charged a $25 fee for not checking in online - she checked in at the airport counter when she arrived. That’s ridiculous. She was old and in a wheelchair. She had a paper boarding pass, and was obviously not tech savvy. She should not be punished for that. 6. They do not have good placement in the terminals. It was always out on the end or down on a subfloor, and we had to walk out on the tarmac almost every time. In Denver. Their home airport! 7. Every time I loaded a new page on the website while buying my tickets or my bags, it was constantly trying to upsell me on some esoteric bundle. Like, a pop-up every time. Very annoying. 8. No screens in the boarding area (at least where we were) to confirm you’re in the right place. Just static gate number signs. I am sure these are standard practices for Frontier, and I should have read more about them before I purchased tickets, but as a result of this single round trip, I do not plan to ever use this cut-rate airline again. I would rather pay the normal amount for a ticket and be treated like a customer instead of a mark.

Our flight was delayed 2 hours and when they changed the the time to 1 hour I wasn't alerted and when I checked the gate the plane was still there but they already shut the doors so I had to buy another flight.

Great except upon arrival it took them a long time to open the doors

Frontier feels like a family I Worked for Eastern Airlines back in the day and I felt the family vibe that I had then. Thank you

Terrible. Delayed my family flight for several hours affecting family plans

Tiny seats, no entertainment, no amenities, delays, they charge for carry on and their allowed personal item is smaller than in other airlines.

The seats are tiny and they don’t recline. The planes are dirty and very small. You have to pay for carry on and even the personal item that you’re allowed is smaller than with other airlines. Flights are usually delayed and there’s no screens or any amenities or entertainment.

I loved the staff on the plane. So friendly and helpful! However, there was an argument and misunderstanding by the staff and a customer at the gate, and the staff member was being unprofessional. When we arrived in Atlanta, we waited 1.5 hrs for our luggage to arrive. When I asked the airport attendant, they said Frontier had the longest wait for luggage out of any airlines, and that they could not be held responsible for the delay.

It was impossible to change a carry-on for a checked bag after the initial selection. The flight was delayed 14 hours "to allow for a late arriving aircraft." The seats were shockingly uncomfortable. This was only the second time I've seen seats that didn't recline in an airline. The first was in an East Bloc airline before the fall if the Iron Curtain.

The experience was terrible. The flight boarded late, then after leaving the gate the plane had had to return to the gate for fuel. After 2 hours on the plane, the flight was canceled. The reasons given for the cancelation didn't sound truthful. and different reasons were given. My 15 year old daughter was flying alone on this flight. When they all disembarked the plane she kept asking the crew what she was supposed to do. No one even gave her the courtesy of a response. No one. It took another 4.75 hrs to be out of customs and baggage. She was re-booked the following day. That flight departed 2 hours late. After all of that, they offered a measly $100 flight voucher with an expiry date of 3 months! All in all a terrible experience. We won't be using Frontier again in the future.

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

Complete your trip to St. Charles with a hotel stay or car rental