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Cheap flights from St. Louis to Belfast from $418

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from St. Louis to Belfast departing on 8/21. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
1 adult, Economy, 0 bags

Find the cheapest flights from St. Louis to Belfast

Cheap round-trip flights

Enter your travel dates to find the best prices.
Multiple Airlines Logo
12:10 pm - 9:30 pm
STL
-
BFS
27h 20m
3 stops
Multiple Airlines Logo
6:30 am - 8:22 pm
BFS
-
STL
19h 52m
2 stops
$1,412Multiple Airlines
Sun, Aug 2 - Mon, Aug 10
Multiple Airlines Logo
12:10 pm - 10:50 pm
STL
-
BFS
28h 40m
3 stops
Multiple Airlines Logo
6:45 am - 8:22 pm
BFS
-
STL
43h 37m
3 stops
$1,427Multiple Airlines
Sun, Jul 26 - Sun, Aug 2
Multiple Airlines Logo
2:40 pm - 10:50 pm
STL
-
BFS
26h 10m
2 stops
Multiple Airlines Logo
6:45 am - 8:22 pm
BFS
-
STL
43h 37m
3 stops
$1,433Multiple Airlines
Sun, Jul 26 - Sun, Aug 2
Multiple Airlines Logo
3:30 pm - 9:20 pm
STL
-
BFS
23h 50m
3 stops
Multiple Airlines Logo
6:30 am - 11:29 pm
BFS
-
STL
22h 59m
3 stops
$1,509Multiple Airlines
Sun, Aug 2 - Mon, Aug 10
Multiple Airlines Logo
2:15 pm - 3:35 pm
STL
-
BFS
19h 20m
2 stops
Multiple Airlines Logo
9:05 pm - 8:07 pm
BFS
-
STL
29h 02m
3 stops
$1,571Multiple Airlines
Mon, Jun 29 - Thu, Jul 2
Multiple Airlines Logo
2:15 pm - 3:35 pm
STL
-
BFS
19h 20m
2 stops
Multiple Airlines Logo
6:40 am - 8:07 pm
BFS
-
STL
19h 27m
2 stops
$1,628Multiple Airlines
Mon, Jun 29 - Thu, Jul 2
Multiple Airlines Logo
8:55 am - 10:50 pm
STL
-
BFS
31h 55m
2 stops
Multiple Airlines Logo
7:20 pm - 1:25 pm
BFS
-
STL
24h 05m
2 stops
$1,641Multiple Airlines
Sun, Jul 26 - Sun, Aug 2
Multiple Airlines Logo
2:40 pm - 4:25 pm
STL
-
BFS
19h 45m
2 stops
Multiple Airlines Logo
9:25 pm - 2:02 pm
BFS
-
STL
22h 37m
2 stops
$1,656Multiple Airlines
Mon, Jul 13 - Sun, Jul 19
Multiple Airlines Logo
2:40 pm - 9:35 pm
STL
-
BFS
24h 55m
2 stops
Multiple Airlines Logo
6:40 am - 11:29 pm
BFS
-
STL
22h 49m
3 stops
$1,661Multiple Airlines
Mon, Jul 27 - Mon, Aug 3
Multiple Airlines Logo
8:40 am - 11:15 am
STL
-
BFS
20h 35m
3 stops
Multiple Airlines Logo
6:10 am - 8:07 pm
BFS
-
STL
43h 57m
3 stops
$1,706Multiple Airlines
Mon, Jun 29 - Thu, Jul 2

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Customize your flight search to find flights from St. Louis to Belfast Intl Airport 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, momondo users made 832,500 searches. Data last updated June 16, 2026.
Use the filters below to find and compare flights from St. Louis to Belfast Intl Airport that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

St. LouisBelfast

STL - BFS

STLBFS

Lambert-St Louis

Sun 8/2

12:10 pm-9:30 pm

3 stops27h 20m

Belfast Intl

Mon 8/10

6:30 am-8:22 pm

2 stops19h 52m

$1,412

St. LouisBelfast

STL - BFS

STLBFS

Lambert-St Louis

Sun 7/26

12:10 pm-10:50 pm

3 stops28h 40m

Belfast Intl

Sun 8/2

6:45 am-8:22 pm

3 stops43h 37m

$1,427

St. LouisBelfast

STL - BFS

STLBFS

Lambert-St Louis

Sun 7/26

2:40 pm-10:50 pm

2 stops26h 10m

Belfast Intl

Sun 8/2

6:45 am-8:22 pm

3 stops43h 37m

$1,433

St. LouisBelfast

STL - BFS

STLBFS

Lambert-St Louis

Sun 8/2

3:30 pm-9:20 pm

3 stops23h 50m

Belfast Intl

Mon 8/10

6:30 am-11:29 pm

3 stops22h 59m

$1,509

St. LouisBelfast

STL - BFS

STLBFS

Lambert-St Louis

Mon 6/29

2:15 pm-3:35 pm

2 stops19h 20m

Belfast Intl

Thu 7/2

9:05 pm-8:07 pm

3 stops29h 02m

$1,571
Quickest round-trip

St. LouisBelfast

STL - BFS

STLBFS

Lambert-St Louis

Mon 6/29

2:15 pm-3:35 pm

2 stops19h 20m

Belfast Intl

Thu 7/2

6:40 am-8:07 pm

2 stops19h 27m

$1,628

St. LouisBelfast

STL - BFS

STLBFS

Lambert-St Louis

Sun 7/26

8:55 am-10:50 pm

2 stops31h 55m

Belfast Intl

Sun 8/2

7:20 pm-1:25 pm

2 stops24h 05m

$1,641

St. LouisBelfast

STL - BFS

STLBFS

Lambert-St Louis

Mon 7/13

2:40 pm-4:25 pm

2 stops19h 45m

Belfast Intl

Sun 7/19

9:25 pm-2:02 pm

2 stops22h 37m

$1,656

St. LouisBelfast

STL - BFS

STLBFS

Lambert-St Louis

Mon 7/27

2:40 pm-9:35 pm

2 stops24h 55m

Belfast Intl

Mon 8/3

6:40 am-11:29 pm

3 stops22h 49m

$1,661

St. LouisBelfast

STL - BFS

STLBFS

Lambert-St Louis

Mon 6/29

8:40 am-11:15 am

3 stops20h 35m

Belfast Intl

Thu 7/2

6:10 am-8:07 pm

3 stops43h 57m

$1,706

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 12 resultsSorted by cheapest first
1
2

When to book flights from St. Louis to Belfast Intl Airport

Are you open to changing your travel dates? Check out the ideal times to fly from St. Louis to Belfast Intl Airport according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

Cheap St. Louis to Belfast Intl Airport (STL to BFS) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from St. Louis to Belfast Intl Airport

Fastest flight time

19h 20m

Direct flights

None
The fastest flight from St. Louis to Belfast Intl Airport takes 19h 20m
There are no direct flights from St. Louis to Belfast Intl Airport. There are no popular flight routes from St. Louis to Belfast Intl Airport.
Search flight deals

Frequently asked questions about flying from St. Louis to Belfast Intl Airport

  • How far is Lambert-St Louis to Belfast Intl by plane?

    Belfast Intl is 3879.0 mi away from Lambert-St Louis. A reasonable flight in good conditions will take 19h 20m.

  • When did momondo last update prices for flights from Lambert-St Louis Airport to Belfast Intl Airport?

    Prices for flights from Lambert-St Louis Airport to Belfast Intl Airport are refreshed on a daily basis.

  • How old do you have to be to fly from Lambert-St Louis Airport to Belfast Intl Airport?

    The minimum age a child must be to fly alone is five but airlines that offer an unaccompanied minor (UNMR) service will have their own age restrictions, including rules around flight length, timings, and stopovers. We always recommend checking with the individual airline you are booking with to travel from Lambert-St Louis Airport to Belfast Intl Airport.

  • What documentation or ID do you need to fly to Belfast Intl Airport?

    The travel and health documents required for your trip to Belfast Intl Airport can vary based on your itinerary and personal situation. As a rule, consider having multiple documents such as a national ID card or driver’s license, and a passport valid for six-months after you plan to arrive at Belfast Intl Airport. We always recommend checking with your airline or a trusted third party such as IATA to get advice.

Frequently asked questions about flying from St. Louis to Belfast Intl Airport

  • How do I get Price Alerts for flights from St. Louis to Belfast Intl Airport?

    Price Alerts will notify you by email when the price for flights to Belfast Intl Airport from St. Louis decreases. To activate this, select your desired travel dates and search for offers. While browsing through offers you’ll see the Price Alert widget toggle. Click it to turn on notifications.

  • How can I save money on flights from St. Louis to Belfast Intl Airport with momondo?

    By using tools like our “Price Calendar”, you can see the best day to fly round-trip for your travels. Our “Price Forecast” tool uses AI to predict whether you should purchase or hold off on booking for potentially cheaper prices. Explore shows you all flight options from a city or airport to build your own unique adventure. The Discover blog also provides valuable insights for saving money while booking your experience. After searching you can toggle on “Price Alerts” to track prices for your desired flight and book at the ideal moment.

  • How does momondo find its flight prices?

    momondo shows deals across 700+ competitors all at once. momondo is active in 30 international markets, so you can have access to a wide range of options from airlines and OTAs alike.

Traveling to a place near Belfast?

Book flights to Belfast if you plan to visit one of these locations
Armagh
Ballymena
Newry
Dungannon

Why use momondo?

Why should I use momondo to find a flight deal from St. Louis to Belfast?

momondo collates all your flight options in one place and lets you filter them to find the perfect flight from St. Louis to Belfast. momondo saves you time and could save you money on your trip.

Can I find flights from St. Louis to Belfast with flexible booking policies on momondo?

All flight searches from St. Louis to Belfast on momondo can be filtered to show those which offer flexible booking policies.

How can momondo help me find flights from St. Louis to Belfast?

Once all potential St. Louis to Belfast flight options are in front of you, momondo lets you sort and filter flights based on preferences such as airline, price and flight times amongst many other options.

I’m not ready to book a flight from St. Louis to Belfast right now. Can momondo alert me if prices change?

If you are not ready to book a flight from St. Louis to Belfast now, use our insights above to find helpful tips or alternatively set up a price alert, where momondo will track prices on flights to Belfast and let you know when they change.

An easier way to manage your Belfast Intl Airport trip

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