$55 Cheap Flights from St. Louis (STL) to Trenton (TTN)

View $55 flight on Thu, Nov 13, 2025Opens in a new window

Popular airlines from St. Louis Lambert Intl. Airport (STL) to Trenton–Mercer Airport (TTN)

Cheap Flights from St. Louis to Trenton (STL-TTN)

Prices were available within the past 7 days and start at $55 for one-way flights and $120 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Thu, Nov 13 - Mon, Nov 17
STL
St. Louis
TTN
Trenton
$120 Roundtrip, found 1 day ago
$120
Roundtrip
found 1 day ago
Select Frontier Airlines flight, departing Thu, Nov 13 from St. Louis to Trenton, returning Mon, Nov 17, priced at $120 found 1 day ago
Frontier Airlines
Sun, Nov 16 - Thu, Nov 20
STL
St. Louis
TTN
Trenton
$127 Roundtrip, found 1 day ago
$127
Roundtrip
found 1 day ago
Select Frontier Airlines flight, departing Sun, Nov 16 from St. Louis to Trenton, returning Thu, Nov 20, priced at $127 found 1 day ago
Frontier Airlines
Fri, Nov 14 - Mon, Nov 17
STL
St. Louis
TTN
Trenton
$137 Roundtrip, found 1 day ago
$137
Roundtrip
found 1 day ago
Select Frontier Airlines flight, departing Fri, Nov 14 from St. Louis to Trenton, returning Mon, Nov 17, priced at $137 found 1 day ago
Frontier Airlines
Thu, Nov 13 - Sat, Nov 15
STL
St. Louis
TTN
Trenton
$140 Roundtrip, found 4 days ago
$140
Roundtrip
found 4 days ago
Select Frontier Airlines flight, departing Thu, Nov 13 from St. Louis to Trenton, returning Sat, Nov 15, priced at $140 found 4 days ago
Frontier Airlines
Fri, Jan 23 - Sun, Jan 25
STL
St. Louis
TTN
Trenton
$148 Roundtrip, found 1 day ago
$148
Roundtrip
found 1 day ago
Select Frontier Airlines flight, departing Fri, Jan 23 from St. Louis to Trenton, returning Sun, Jan 25, priced at $148 found 1 day ago
Frontier Airlines
Thu, Dec 11 - Sat, Dec 13
STL
St. Louis
TTN
Trenton
$160 Roundtrip, found 4 days ago
$160
Roundtrip
found 4 days ago
Select Frontier Airlines flight, departing Thu, Dec 11 from St. Louis to Trenton, returning Sat, Dec 13, priced at $160 found 4 days ago
Frontier Airlines
Thu, Dec 11 - Fri, Dec 12
STL
St. Louis
TTN
Trenton
$173 Roundtrip, found 4 days ago
$173
Roundtrip
found 4 days ago
Select Frontier Airlines flight, departing Thu, Dec 11 from St. Louis to Trenton, returning Fri, Dec 12, priced at $173 found 4 days ago
Frontier Airlines
Fri, Dec 12 - Sun, Dec 14
STL
St. Louis
TTN
Trenton
$176 Roundtrip, found 3 days ago
$176
Roundtrip
found 3 days ago
Select Frontier Airlines flight, departing Fri, Dec 12 from St. Louis to Trenton, returning Sun, Dec 14, priced at $176 found 3 days ago
Frontier Airlines
Thu, Nov 6 - Thu, Nov 13
STL
St. Louis
TTN
Trenton
$179 Roundtrip, found 3 days ago
$179
Roundtrip
found 3 days ago
Select Frontier Airlines flight, departing Thu, Nov 6 from St. Louis to Trenton, returning Thu, Nov 13, priced at $179 found 3 days ago
American Airlines
Thu, Dec 18 - Tue, Jan 13
STL
St. Louis
TTN
Trenton
$351 Roundtrip, found 1 day ago
$351
Roundtrip
found 1 day ago
Select American Airlines flight, departing Thu, Dec 18 from St. Louis to Trenton, returning Tue, Jan 13, priced at $351 found 1 day ago

Alternative airports near Trenton

Prices were available within the past 7 days. Prices and availability are subject to change.

Select flight to Mercer TTN. Cheapest and Closest option available. Average driving time to city center is 10 minutes. Flights from $120
TTN
Mercer
CheapestClosest
Average driving time to city center10 min
Flights from $120

Frequently asked questions

How much does a flight from Lambert-St. Louis Intl. Airport (STL) to Mercer Airport (TTN) cost?
Snag a cheap one-way flight from $55 or cheap return flight from $120 from Lambert-St. Louis Intl. Airport (STL) to Mercer Airport (TTN) with Expedia. Enter your travel dates and sort by "Price (lowest to highest)" to see our cheapest flight offers on this route.
What is the cheapest month to fly from Lambert-St. Louis Intl. Airport (STL) to Mercer Airport (TTN)?
Planning your getaway for November can help you save, as it's the cheapest month for flights between STL and TTN. You'll usually find the lowest fares during off-peak months.
What is the cheapest airline that flies from Lambert-St. Louis Intl. Airport (STL) to Mercer Airport (TTN)?
Use the filters on Expedia to compare different airlines and find the most affordable carrier that'll take you from STL to TTN. Then, sort your results by "Price (lowest to highest)" to score the best deal available.
How many flights per day from Lambert-St. Louis Intl. Airport (STL) to Mercer Airport (TTN)?
Nonstop flights from Lambert-St. Louis Intl. Airport (STL) to Mercer Airport (TTN) aren't available daily, so you'll have to take a flight with a layover. Explore your options with our filter tool. Enter your travel dates and choose either "1 Stop" or "2+ Stops."
What day of the week has the most flights from STL to TTN?
You'll typically find Tuesday the quietest day for flights, while Fridays are often the busiest.* However this can vary from season to season and during peak travel times or public holidays.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from Lambert-St. Louis Intl. Airport (STL) to Mercer Airport (TTN)?
To arrive at Mercer Airport (TTN) on schedule, pick a flight that leaves from Lambert-St. Louis Intl. Airport (STL) before 3 PM. The chance of cancellations is 22% higher, on average, for departures after this time.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
What airports do you fly into for Trenton from Lambert-St. Louis Intl. Airport (STL)?
Book a direct flight from Lambert-St. Louis Intl. Airport (STL) to Trenton and touch down at any one of these airports:

  • LaGuardia Airport (LGA)
  • Liberty Intl. Airport (EWR)
  • Philadelphia Intl. Airport (PHL)

Is it cheaper to buy a plane ticket from Lambert-St. Louis Intl. Airport (STL) to Mercer Airport (TTN) last-minute?
Last-minute bookings from STL to TTN are generally more expensive. To lock in the lowest prices, start searching for flights well ahead of time. That said, if you're flexible with your travel plans, you may score a cheap fare right before you leave.
Is it cheaper to book a STL to TTN flight and hotel package?
Securing a STL to TTN flight and hotel package is generally cheaper than booking separately. With Expedia, you can enjoy the convenience of organizing your trip all in one place. Pick from our extensive range of accommodations and then add flights, activities and car rentals to your booking. Bundle everything together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Lambert-St. Louis Intl. Airport (STL) to Mercer Airport (TTN)?
You can usually cancel or reschedule your STL to TTN flight. However, if it's been more than 24 hours since booking, additional fees may apply. Check your airline's policies in your itinerary to see what changes are possible and whether any costs are involved. You'll also find more information on our Customer Service portal.

Travel information

Origin airport
Lambert-St. Louis Intl.
Destination airport
Mercer
Airlines serving
American Airlines, Frontier Airlines
Roundtrip price
$120
Distance
834 mi

Book with confidence

St. Louis to Trenton Flights

The cheapest times to fly from St. Louis to Trenton

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from St. Louis to Trenton are during the month of November. You can find some of the cheapest flights from St. Louis to Trenton with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from St. Louis to Trenton

Sunday is one of the best days to book for cheap flights from St. Louis to Trenton: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

 

How to find cheap round-trip tickets from St. Louis to Trenton

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from St. Louis to Trenton in 2025. You can also book with separate airlines for your outbound and return journeys, from $55 one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

 

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap St. Louis to Trenton flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

 

You could also save big by booking one of Expedia's vacation packages. Bundling together your St. Louis to Trenton airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

 

*Terms apply.

 

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

 

St. Louis to Trenton Flights

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*Available to One Key members.