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Cheap flights from St. Louis to Harlingen from $138

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 Harlingen departing on 8/20. 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

Discover deals from 900+ travel sites with momondo.

Find the cheapest flights from St. Louis to Harlingen

Cheap round-trip flights

Enter your travel dates to find the best prices.
Southwest Logo
10:55 am - 5:15 pm
STL
-
HRL
6h 20m
1 stop
Southwest Logo
4:40 pm - 9:50 pm
HRL
-
STL
5h 10m
1 stop
$275Southwest
Thu, Aug 20 - Thu, Aug 27
American Airlines Logo
5:43 am - 9:58 am
STL
-
HRL
4h 15m
1 stop
American Airlines Logo
5:28 pm - 11:43 pm
HRL
-
STL
6h 15m
1 stop
$275American Airlines
Sat, Sep 12 - Tue, Sep 22
Southwest Logo
3:45 pm - 10:35 pm
STL
-
HRL
6h 50m
2 stops
Southwest Logo
4:40 pm - 9:50 pm
HRL
-
STL
5h 10m
1 stop
$280Southwest
Thu, Aug 20 - Thu, Aug 27
Southwest Logo
4:20 pm - 9:00 pm
STL
-
HRL
4h 40m
1 stop
Southwest Logo
6:35 am - 1:55 pm
HRL
-
STL
7h 20m
2 stops
$280Southwest
Sat, Sep 12 - Tue, Sep 22
Southwest Logo
5:15 am - 10:50 am
STL
-
HRL
5h 35m
2 stops
Southwest Logo
6:35 am - 1:55 pm
HRL
-
STL
7h 20m
2 stops
$285Southwest
Sat, Sep 12 - Tue, Sep 22
American Airlines Logo
5:42 am - 10:04 am
STL
-
HRL
4h 22m
1 stop
American Airlines Logo
3:17 pm - 8:26 pm
HRL
-
STL
5h 09m
1 stop
$350American Airlines
Tue, Aug 11 - Sat, Aug 15
United Airlines Logo
2:55 pm - 7:47 pm
STL
-
HRL
4h 52m
1 stop
United Airlines Logo
5:05 am - 10:02 am
HRL
-
STL
4h 57m
1 stop
$355United Airlines
Tue, Nov 3 - Wed, Nov 4
United Airlines Logo
2:55 pm - 7:47 pm
STL
-
HRL
4h 52m
1 stop
United Airlines Logo
5:05 am - 2:30 pm
HRL
-
STL
9h 25m
2 stops
$360United Airlines
Tue, Nov 3 - Wed, Nov 4
United Airlines Logo
8:30 am - 4:01 pm
STL
-
HRL
7h 31m
1 stop
United Airlines Logo
5:05 am - 10:02 am
HRL
-
STL
4h 57m
1 stop
$365United Airlines
Tue, Nov 3 - Wed, Nov 4
United Airlines Logo
5:00 am - 4:01 pm
STL
-
HRL
11h 01m
2 stops
United Airlines Logo
5:05 am - 3:43 pm
HRL
-
STL
10h 38m
2 stops
$366United Airlines
Tue, Nov 3 - Wed, Nov 4

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Southwest flights from St. Louis to Harlingen

Our best Southwest deals on St. Louis to Harlingen flight tickets
Southwest
Aug 20
STL10:55 amLambert-St Louis
6h 20m
1 stop
HRL5:15 pmHarlingen Valley Intl
Aug 27
HRL4:40 pmHarlingen Valley Intl
5h 10m
1 stop
STL9:50 pmLambert-St Louis
$275
Southwest
Aug 20
STL3:45 pmLambert-St Louis
6h 50m
2 stops
HRL10:35 pmHarlingen Valley Intl
Aug 27
HRL4:40 pmHarlingen Valley Intl
5h 10m
1 stop
STL9:50 pmLambert-St Louis
$280
Southwest
Sep 12
STL5:15 amLambert-St Louis
5h 35m
2 stops
HRL10:50 amHarlingen Valley Intl
Sep 22
HRL6:35 amHarlingen Valley Intl
7h 20m
2 stops
STL1:55 pmLambert-St Louis
$285

United Airlines flights from St. Louis to Harlingen

Our best United Airlines deals on St. Louis to Harlingen flight tickets
United Airlines
Nov 3
STL2:55 pmLambert-St Louis
4h 52m
1 stop
HRL7:47 pmHarlingen Valley Intl
Nov 4
HRL5:05 amHarlingen Valley Intl
4h 57m
1 stop
STL10:02 amLambert-St Louis
$355
United Airlines
Nov 3
STL2:55 pmLambert-St Louis
4h 52m
1 stop
HRL7:47 pmHarlingen Valley Intl
Nov 4
HRL5:05 amHarlingen Valley Intl
9h 25m
2 stops
STL2:30 pmLambert-St Louis
$360
United Airlines
Nov 3
STL8:30 amLambert-St Louis
7h 31m
1 stop
HRL4:01 pmHarlingen Valley Intl
Nov 4
HRL5:05 amHarlingen Valley Intl
4h 57m
1 stop
STL10:02 amLambert-St Louis
$365

momondo Fare Finder

 
Customize your flight search to find flights from St. Louis to Harlingen 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 July 28, 2026.
Use the filters below to find and compare flights from St. Louis to Harlingen that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

St. LouisHarlingen

STL - HRL

STLHRL

Lambert-St Louis

Thu 8/20

10:55 am-5:15 pm

1 stop6h 20m

Harlingen Valley Intl

Thu 8/27

4:40 pm-9:50 pm

1 stop5h 10m

$275

St. LouisHarlingen

STL - HRL

STLHRL

Lambert-St Louis

Sat 9/12

5:43 am-9:58 am

1 stop4h 15m

Harlingen Valley Intl

Tue 9/22

5:28 pm-11:43 pm

1 stop6h 15m

$275

St. LouisHarlingen

STL - HRL

STLHRL

Lambert-St Louis

Thu 8/20

3:45 pm-10:35 pm

2 stops6h 50m

Harlingen Valley Intl

Thu 8/27

4:40 pm-9:50 pm

1 stop5h 10m

$280

St. LouisHarlingen

STL - HRL

STLHRL

Lambert-St Louis

Sat 9/12

4:20 pm-9:00 pm

1 stop4h 40m

Harlingen Valley Intl

Tue 9/22

6:35 am-1:55 pm

2 stops7h 20m

$280

St. LouisHarlingen

STL - HRL

STLHRL

Lambert-St Louis

Sat 9/12

5:15 am-10:50 am

2 stops5h 35m

Harlingen Valley Intl

Tue 9/22

6:35 am-1:55 pm

2 stops7h 20m

$285
Quickest round-trip

St. LouisHarlingen

STL - HRL

STLHRL

Lambert-St Louis

Tue 8/11

5:42 am-10:04 am

1 stop4h 22m

Harlingen Valley Intl

Sat 8/15

3:17 pm-8:26 pm

1 stop5h 09m

$350

St. LouisHarlingen

STL - HRL

STLHRL

Lambert-St Louis

Tue 11/3

2:55 pm-7:47 pm

1 stop4h 52m

Harlingen Valley Intl

Wed 11/4

5:05 am-10:02 am

1 stop4h 57m

$355

St. LouisHarlingen

STL - HRL

STLHRL

Lambert-St Louis

Tue 11/3

2:55 pm-7:47 pm

1 stop4h 52m

Harlingen Valley Intl

Wed 11/4

5:05 am-2:30 pm

2 stops9h 25m

$360

St. LouisHarlingen

STL - HRL

STLHRL

Lambert-St Louis

Tue 11/3

8:30 am-4:01 pm

1 stop7h 31m

Harlingen Valley Intl

Wed 11/4

5:05 am-10:02 am

1 stop4h 57m

$365

St. LouisHarlingen

STL - HRL

STLHRL

Lambert-St Louis

Tue 11/3

5:00 am-4:01 pm

2 stops11h 01m

Harlingen Valley Intl

Wed 11/4

5:05 am-3:43 pm

2 stops10h 38m

$366

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 16 resultsSorted by cheapest first
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See travel insights to Harlingen from

How to get the cheapest flight ticket from St. Louis to Harlingen

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the cheapest month to fly to Harlingen?

If you aren’t able to travel during the month of October, then book flights to Harlingen from St. Louis during January instead. Flights to Harlingen in January, while not as cheap as those in October, still average around $256.

Can stopping save me money on St. Louis to Harlingen flights?

You could potentially save up to 5% on your flight if you consider stops on a St. Louis to Harlingen flight.

When to book flights from St. Louis to Harlingen

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

Cheap St. Louis to Harlingen (STL to HRL) flight deals and tips

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

Fastest flight time

4h 00m

Direct flights

None
The fastest flight from St. Louis to Harlingen takes 4h 00m
There are no direct flights from St. Louis to Harlingen. There are no popular flight routes from St. Louis to Harlingen.
Search flight deals

Frequently asked questions about flying from St. Louis to Harlingen

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

    There are 962.6 mi between Lambert-St Louis and Harlingen Valley Intl. In terms of flight time, this usually takes a little over 4h 00m.

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

    Prices for flights from Lambert-St Louis Airport to Harlingen Valley Intl Airport were last updated today.

  • How many operators does momondo search for flights from Lambert-St Louis Airport to Harlingen Valley Intl Airport?

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

    Although the minimum age for a child to fly alone is five, airlines that offer an unaccompanied minor (UMNR) service may have their own age limits, which could be impacted by factors such as flight length, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Lambert-St Louis Airport to Harlingen Valley Intl Airport.

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

    The travel and health documents required for your trip to Harlingen Valley 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 Harlingen Valley Intl Airport. We always recommend checking with your airline or a trusted third party such as IATA to get advice.

  • What is the most popular airline from St. Louis to Harlingen?

Best airlines flying from St. Louis to Harlingen

Compare and see reviews for airlines that fly from St. Louis to Harlingen with momondo
Airline
Rating
Free Cancellation
Price
American AirlinesPriceFrom $212Free CancellationRating
7.1
11,845 reviews
Search American Airlines flights
SouthwestPriceFrom $216Free CancellationRating
8.0
4,228 reviews
Search Southwest flights

Why use momondo?

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

momondo compares prices from hundreds of airlines and agents so you can find and book the best deal on flights from St. Louis to Harlingen. Millions of users trust and use momondo every year so you are in good hands.

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

Yes. momondo allows you to filter the results for St. Louis to Harlingen flights to just show those with flexible booking policies.

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

Once you have performed a search for St. Louis to Harlingen flights, momondo helps you find the right one by offering useful filters to narrow down your flight selection. Flights can be filtered by multiple factors such as airline, airport and price; but also by other criteria like aircraft type and payment method.

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

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

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