$61 Cheap Flights from Trenton (TTN) to St. Louis (STL)

View $61 flight on Thu, Jan 22, 2026Opens in a new window

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

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

Prices were available within the past 7 days and start at $61 for one-way flights and $110 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Thu, Nov 20 - Sat, Dec 6
TTN
Trenton
STL
St. Louis
$110 Roundtrip, found 5 days ago
$110
Roundtrip
found 5 days ago
Select Frontier Airlines flight, departing Thu, Nov 20 from Trenton to St. Louis, returning Sat, Dec 6, priced at $110 found 5 days ago
Frontier Airlines
Thu, Dec 11 - Sat, Dec 13
TTN
Trenton
STL
St. Louis
$120 Roundtrip, found 9 hours ago
$120
Roundtrip
found 9 hours ago
Select Frontier Airlines flight, departing Thu, Dec 11 from Trenton to St. Louis, returning Sat, Dec 13, priced at $120 found 9 hours ago
Frontier Airlines
Thu, Nov 27 - Thu, Dec 4
TTN
Trenton
STL
St. Louis
$127 Roundtrip, found 1 day ago
$127
Roundtrip
found 1 day ago
Select Frontier Airlines flight, departing Thu, Nov 27 from Trenton to St. Louis, returning Thu, Dec 4, priced at $127 found 1 day ago
Frontier Airlines
Thu, Jan 29 - Sun, Feb 1
TTN
Trenton
STL
St. Louis
$134 Roundtrip, found 3 hours ago
$134
Roundtrip
found 3 hours ago
Select Frontier Airlines flight, departing Thu, Jan 29 from Trenton to St. Louis, returning Sun, Feb 1, priced at $134 found 3 hours ago
Frontier Airlines
Thu, Nov 27 - Thu, Dec 4
TTN
Trenton
STL
St. Louis
$137 Roundtrip, found 2 hours ago
$137
Roundtrip
found 2 hours ago
Select Frontier Airlines flight, departing Thu, Nov 27 from Trenton to St. Louis, returning Thu, Dec 4, priced at $137 found 2 hours ago
Frontier Airlines
Thu, Jan 15 - Sun, Jan 18
TTN
Trenton
STL
St. Louis
$138 Roundtrip, found 10 hours ago
$138
Roundtrip
found 10 hours ago
Select Frontier Airlines flight, departing Thu, Jan 15 from Trenton to St. Louis, returning Sun, Jan 18, priced at $138 found 10 hours ago
Frontier Airlines
Sat, Nov 22 - Tue, Nov 25
TTN
Trenton
STL
St. Louis
$144 Roundtrip, found 3 days ago
$144
Roundtrip
found 3 days ago
Select Frontier Airlines flight, departing Sat, Nov 22 from Trenton to St. Louis, returning Tue, Nov 25, priced at $144 found 3 days ago
Frontier Airlines
Sun, Dec 7 - Fri, Dec 12
TTN
Trenton
STL
St. Louis
$148 Roundtrip, found 1 day ago
$148
Roundtrip
found 1 day ago
Select Frontier Airlines flight, departing Sun, Dec 7 from Trenton to St. Louis, returning Fri, Dec 12, priced at $148 found 1 day ago
Frontier Airlines
Thu, Nov 27 - Fri, Dec 5
TTN
Trenton
STL
St. Louis
$151 Roundtrip, found 7 hours ago
$151
Roundtrip
found 7 hours ago
Select Frontier Airlines flight, departing Thu, Nov 27 from Trenton to St. Louis, returning Fri, Dec 5, priced at $151 found 7 hours ago
American Airlines
Sun, Feb 15 - Thu, Feb 19
TTN
Trenton
STL
St. Louis
$351 Roundtrip, found 15 hours ago
$351
Roundtrip
found 15 hours ago
Select American Airlines flight, departing Sun, Feb 15 from Trenton to St. Louis, returning Thu, Feb 19, priced at $351 found 15 hours ago

Alternative airports near St. Louis

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

Select flight to Lambert-St. Louis Intl. STL. Cheapest option available. Average driving time to city center is 20 minutes. Flights from $623
STL
Lambert-St. Louis Intl.
Cheapest
Average driving time to city center20 min
Flights from $623

Frequently asked questions

How much does a flight from Mercer Airport (TTN) to Lambert-St. Louis Intl. Airport (STL) cost?
Secure a cheap one-way flight from $61 or cheap return flight from $110 from Mercer Airport (TTN) to Lambert-St. Louis Intl. Airport (STL) with Expedia. Enter your travel dates and sort by "Price (lowest to highest)" to find our cheapest flight offers on this route.
What is the cheapest month to fly from Mercer Airport (TTN) to Lambert-St. Louis Intl. Airport (STL)?
The cheapest month to fly from TTN to STL is November, when there's less demand. Off-peak months are generally when you'll find lower airfares between these airports.
Which airlines fly direct from Mercer Airport (TTN) to Lambert-St. Louis Intl. Airport (STL)?
While Trenton, NJ (TTN-Mercer) doesn't offer any direct flights to Lambert-St. Louis Intl. Airport (STL), other airports have nonstop options. Departing from Liberty Intl. Airport (EWR) will get you to St. Louis without any layovers.
What is the cheapest airline that flies from Mercer Airport (TTN) to Lambert-St. Louis Intl. Airport (STL)?
Use the filter tool on Expedia to compare airlines and find the most affordable carrier that'll fly you from TTN to STL. Then, sort your results by "Price (lowest to highest)" to snap up the best deal available.
How many flights per day from Mercer Airport (TTN) to Lambert-St. Louis Intl. Airport (STL)?
You'll need to book a flight with a layover when traveling from Mercer Airport (TTN) to Lambert-St. Louis Intl. Airport (STL). There are no daily direct flights on this route. However, simply filter your search to include one or two stops to discover the best option for your trip.
What day of the week has the most flights from TTN to STL?
Usually you'll have the most choice when it comes to flights on a Friday. Tuesdays tend to be the quietest.* But this can vary depending on the airline, season and other factors.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from Mercer Airport (TTN) to Lambert-St. Louis Intl. Airport (STL)?
Select a flight from Mercer Airport (TTN) to Lambert-St. Louis Intl. Airport (STL) that leaves before 3 PM to reduce the likelihood of delays. Departures after this time are on average 22% more likely to be canceled.**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.
Is it cheaper to buy a plane ticket from Mercer Airport (TTN) to Lambert-St. Louis Intl. Airport (STL) last-minute?
Booking your plane ticket from TTN to STL just before your getaway is usually more expensive. But if you're flexible with your schedule, you could score a cheap last-minute fare.
Is it cheaper to book a TTN to STL flight and hotel package?
You'll generally save money by booking a TTN to STL flight and hotel package compared to booking separately. In fact, travelers could save hundreds of dollars by bundling with Expedia. And it's simple to manage it all in one place. After choosing your preferred accommodations and flights, you can add extras like car rentals, tours and activities.
Can I cancel or change the date of my flight from Mercer Airport (TTN) to Lambert-St. Louis Intl. Airport (STL)?
In most cases, you can reschedule or cancel your TTN to STL flight. However, there may be additional charges, especially if you booked over 24 hours ago. Check your itinerary for the airline's fees and guidelines on flight changes, or if you need more details, visit our Customer Service portal.

Travel information

Origin airport
Mercer
Destination airport
Lambert-St. Louis Intl.
Airlines serving
American Airlines, Frontier Airlines
Roundtrip price
$110
Distance
834 mi

Book with confidence

Trenton to St. Louis Flights

The cheapest times to fly from Trenton to St. Louis

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 Trenton to St. Louis are during the month of November. You can find some of the cheapest flights from Trenton to St. Louis with Expedia's search tool and vast selection of airlines.

 

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

Sunday is one of the best days to book for cheap flights from Trenton to St. Louis: 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 Trenton to St. Louis

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 Trenton to St. Louis in 2025. You can also book with separate airlines for your outbound and return journeys, from $61 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 Trenton to St. Louis 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 Trenton to St. Louis 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.

 

Trenton to St. Louis Flights

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