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$353 Cheap Flights from St. Louis (STL) to Sofia (SOF)

View $353 flight on Tue, Oct 20, 2026Opens in a new window

Popular airlines from St. Louis Lambert Intl. Airport (STL) to Sofia Airport (SOF)

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Cheap Flights from St. Louis to Sofia (STL-SOF)

Prices were available within the past 7 days and start at $353 for one-way flights and $770 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Lufthansa
Wed, Mar 17 - Wed, Mar 24
STL
St. Louis
SOF
Sofia
$770 Roundtrip, found 2 days ago
$770
Roundtrip
found 2 days ago
Select Lufthansa flight, departing Wed, Mar 17 from St. Louis to Sofia, returning Wed, Mar 24, priced at $770 found 2 days ago
United
Wed, Mar 17 - Wed, Mar 24
STL
St. Louis
SOF
Sofia
$770 Roundtrip, found 2 days ago
$770
Roundtrip
found 2 days ago
Select United flight, departing Wed, Mar 17 from St. Louis to Sofia, returning Wed, Mar 24, priced at $770 found 2 days ago
United
Wed, Mar 17 - Wed, Mar 24
STL
St. Louis
SOF
Sofia
$772 Roundtrip, found 2 days ago
$772
Roundtrip
found 2 days ago
Select United flight, departing Wed, Mar 17 from St. Louis to Sofia, returning Wed, Mar 24, priced at $772 found 2 days ago
Air Canada
Wed, Mar 17 - Wed, Mar 24
STL
St. Louis
SOF
Sofia
$774 Roundtrip, found 2 days ago
$774
Roundtrip
found 2 days ago
Select Air Canada flight, departing Wed, Mar 17 from St. Louis to Sofia, returning Wed, Mar 24, priced at $774 found 2 days ago
Air Canada
Wed, Mar 17 - Wed, Mar 24
STL
St. Louis
SOF
Sofia
$776 Roundtrip, found 2 days ago
$776
Roundtrip
found 2 days ago
Select Air Canada flight, departing Wed, Mar 17 from St. Louis to Sofia, returning Wed, Mar 24, priced at $776 found 2 days ago
Lufthansa
Wed, Nov 4 - Wed, Nov 11
STL
St. Louis
SOF
Sofia
$777 Roundtrip, found 3 days ago
$777
Roundtrip
found 3 days ago
Select Lufthansa flight, departing Wed, Nov 4 from St. Louis to Sofia, returning Wed, Nov 11, priced at $777 found 3 days ago
United
Wed, Mar 17 - Wed, Mar 24
STL
St. Louis
SOF
Sofia
$778 Roundtrip, found 2 days ago
$778
Roundtrip
found 2 days ago
Select United flight, departing Wed, Mar 17 from St. Louis to Sofia, returning Wed, Mar 24, priced at $778 found 2 days ago
United
Wed, Mar 17 - Wed, Mar 24
STL
St. Louis
SOF
Sofia
$780 Roundtrip, found 2 days ago
$780
Roundtrip
found 2 days ago
Select United flight, departing Wed, Mar 17 from St. Louis to Sofia, returning Wed, Mar 24, priced at $780 found 2 days ago
British Airways
Tue, Nov 10 - Wed, Nov 18
STL
St. Louis
SOF
Sofia
$800 Roundtrip, found 6 days ago
$800
Roundtrip
found 6 days ago
Select British Airways flight, departing Tue, Nov 10 from St. Louis to Sofia, returning Wed, Nov 18, priced at $800 found 6 days ago
KLM
Wed, Mar 17 - Wed, Mar 24
STL
St. Louis
SOF
Sofia
$838 Roundtrip, found 2 days ago
$838
Roundtrip
found 2 days ago
Select KLM flight, departing Wed, Mar 17 from St. Louis to Sofia, returning Wed, Mar 24, priced at $838 found 2 days ago

What you need to know for your flight from Lambert-St. Louis Intl. to Sofia

St. Louis (STL) to Sofia (SOF) at a glance

Travel from St. Louis (STL) to Sofia (SOF) with a range of airlines on this international long-haul route. Discover options for flights from STL that cater to different budgets and schedules, whether you’re interested in full-service carriers or more economical choices. As you plan your visit to explore Sofia's renowned attractions and vibrant neighborhoods, find essential details for flights departing from Lambert-St. Louis International Airport (STL) to Sofia Airport (SOF).

  • Fastest flight duration: around 11 hours in-flight, plus roughly 2h 45m layover with one stop
  • Route distance: roughly 5,500 miles (8,850 km)
  • Flights per week: around 7 departures on average
  • Typical fares (one-way): economy tickets often range from $310–$900, depending on seasonality and how far ahead you book

Flights from Lambert-St. Louis International Airport (STL) to Sofia Airport (SOF)

Based on the latest traveler bookings, here are the top airlines favored for flights from St. Louis to Sofia, usually featuring one-stop and multi-stop options. Many travelers opt for layovers at Frankfurt International Airport (FRA), which typically has a layover time of around 2 hours and 45 minutes. This allows you to tailor your journey by balancing cost, overall travel duration, and cabin class for the ideal itinerary.

  • Lufthansa: This full-service airline provides a convenient one-stop journey, with one-way prices generally between $310 and $850. It operates around 46% of all flights on this route, featuring an in-flight duration of 11 hours and an overall travel time of approximately 13 hours and 45 minutes, including layover time.
  • United: Another full-service option, United offers multi-stop itineraries, with one-way fares typically ranging from $310 to $790. It makes up about 33% of departures for this route, boasting a flight time of 12 hours and a total journey duration of around 16 hours and 45 minutes, factoring in layovers.
  • Delta: Operating as a full-service carrier, Delta provides multi-stop services with one-way ticket prices usually between $475 and $1,145. It represents roughly 12% of the flights on this route, featuring an in-flight duration of 12 hours and a complete journey time of about 16 hours and 45 minutes, including layovers.

Alternative route from St. Louis (STL) to Sofia (SOF)

  • Belleville to Sofia (BLV-SOF): MidAmerica-St. Louis Airport (BLV) is located approximately 33 miles from Lambert-St. Louis International Airport (STL).

How to find the best prices for flights from St. Louis (STL) to Sofia (SOF)

Getting some of the best deals on flights from St. Louis to Sofia is all about timing and flexibility. Here are some key tips to help you save:

  1. Best times to book and fly: cheaper fares are usually found when booking at least two months in advance, which coincides with the timing of most travelers. Afternoon departures, between 12 PM and 6 PM, often offer lower prices and are also popular flight times. Additionally, flying on Wednesday provides both cheaper rates and is the most favored travel day.
  2. Set up price alerts: stay updated on price changes by using Expedia's Price Tracker. Receive alerts when fares drop for your selected route.
  3. Bundle and save: bundle your flight and hotel to save on Expedia, or unlock a hotel deal after booking your flight.*
  4. Compare flight options: use Expedia's search tool to compare airlines, routes, direct vs. non-direct flights, and flight times. You can also sort by price to find the most affordable options.
  5. Stay flexible with dates: being open to different travel days can sometimes help you find better prices on flights and hotels.
  6. Think about luggage: nowadays, it's important to check the airline's baggage policies to find the best value. That may be paying for an additional carry-on bag or booking a ticket with checked luggage included. Either way, double-check your allowance before confirming your booking to avoid excess baggage fees at the airport.

*Members only. Savings vary and are not available on all bundles. Select hotels.

Arriving at Sofia Airport from Lambert-St. Louis International Airport

Sofia welcomes travelers from St. Louis with a range of transport options based on price, convenience, and proximity. Here's how to reach Sofia efficiently:

  • Hotel transfer: Transfers offer a convenient way to reach your hotel in Sofia, with private rides that can be arranged in advance.
  • Car rental: Renting a car from Sofia Airport is a great option if you plan to explore and sightsee beyond the city. Browse cheap car rentals at Sofia Airport on Expedia.
  • Taxi/ride-hailing: Taxis and ride-hailing services may be available from designated pickup areas outside the terminal, check locally on arrival.
  • Public transportation: From Sofia Airport, several transport options are conveniently located within a short drive. Sofia Airport Terminal 2 Station, a metro station, is about 0.7 miles from the airport, while Sofia Seaport, a seaport, is approximately 4.6 miles away. Additionally, Sofia Central Station, a train station, is situated around 5 miles from the airport, all typically reachable by car.

Frequently asked questions

How much does a flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF) cost?
You can find cheap one-way flights from $353 and cheap return flights from $770 St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF) with Expedia. One-way flights generally range between $483 and $1614, and roundtrip flights usually range from $850 to $6144. Flight prices vary based on the month and day of the week you want to travel, as well as the airline and how far in advance you book your ticket. Filter your search on Expedia by "Price (lowest to highest)" to see the cheapest fares first, and use the Price Tracking tool to receive alerts when St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF) ticket fares go up or down.*Typical price ranges based on flights available on Expedia in the last year. Prices include multi-airline options.
What is the cheapest month to fly from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF)?
The cheapest month to fly from STL to SOF is March when demand is low. Traveling in off-peak or shoulder months is usually a good way to secure cheap tickets, just remember to avoid flying during holidays if you're able to. Use the calendar view in your search to see which months have low fares on this route.
Which airlines fly direct from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF)?
Enter STL to SOF and your travel dates, then apply the 'Nonstop' filter to see only direct flights.
What is the cheapest airline that flies from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF)?
KLM is one of the cheapest airlines offering connecting flights from St. Louis, MO (STL) to Sofia (SOF), with round-trip tickets starting from around $721 with a layover in Hartsfield-Jackson Atlanta Intl. (ATL). Use Expedia's search tool to compare the prices and schedules of airlines that fly this route to find the best option for your plans and budget.*Prices based on flights available on Expedia in the last year.
How do I find cheap flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF)?
To find a cheap flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF), be flexible with your dates. Traveling outside of peak vacation months and booking a mid-week flight can help you save. Early morning and late night flights are often more affordable, too. Expedia allows you to compare flight times, airlines and routes all in one place to find low fares. You can also set up Price Tracking and receive alerts when fares go up or down.
What is the best time to fly from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF)?
The best time to fly is usually mid-week (Tuesday or Wednesday) and during early morning hours as flights tend to be cheaper, less crowded, and generally more on-time. Avoid major holidays and peak vacation seasons for smoother travel. Combining off-peak days and hours often gives the best combination of cost, comfort, and convenience.
What is the earliest flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF)?
Sort flights by "Departure (earliest)" on Expedia to find the earliest flight from STL to SOF. To compare more early flights, use the "Early Morning" and "Morning" filters in your search.
What are the most popular departure times for flights from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF)?
The most popular departure times for flights from Lambert-St. Louis International Airport (STL) to Sofia (SOF) are in the afternoon, from 3pm to 6pm. About 33% of passengers prefer this time window. Many major carriers, including Lufthansa, United Airlines, and Air Canada, offer flights during this window. This timing is favored as it allows you to travel after a productive day.
How long does it take to fly from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF)?
Flying from STL to SOF with a connection usually takes about 23 hours, traveling roughly 5,449 miles. Keep in mind that actual flight times can vary due to wind patterns, weather, and air traffic.
Can you fly business or first class from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF)?
Business class is available on flights from STL to SOF. Airlines that offer business class service on this route include:

  • Air Canada
  • Lufthansa
  • United Airlines
  • Delta Air Lines

How do I earn miles on a St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF) flight with Expedia?
It's easy to earn miles on a St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF) flight when you book with Expedia. Before you confirm your booking, simply select your frequent flyer program and enter your program number. As a member of One Key™, you can also earn OneKeyCash™* on top of your airline miles when you book with Expedia.*Excludes taxes and fees. OneKeyCash is not redeemable for cash and can only be used on Expedia and other participating brands.
Is it cheaper to buy a plane ticket from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF) at the last minute?
Typically, booking a last minute flight from St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF) will be more expensive than booking in advance. As the departure date approaches, there are usually fewer seats available which can drive up the cost. However, if there's some wiggle room with your travel dates and times, you could bag a cheap last-minute fare.
Is it cheaper to book a St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF) flight and hotel package?
Securing a St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF) Sofia Vacation Packages is usually cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your travels all in one place. Select from our extensive range of stays 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 St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF)?
If you booked your St. Louis, MO (STL-Lambert-St. Louis Intl.) to Sofia (SOF) flight within the last 24 hours, you may be able to modify or cancel it without any fees. Depending on the airline and the type of ticket you have, additional charges may apply for changes beyond this timeframe. Airline policies and contact information can be found in your itinerary or confirmation email. Or, head to our Customer Service portal if you'd like more information.

Travel information

Origin airport
Lambert-St. Louis Intl.
Destination airport
Sofia
Airlines serving
Air Canada, Air France, Austrian Airlines, British Airways, KLM, Lufthansa, Turkish Airlines, United
Roundtrip price
$770
Distance
5448 mi

Book with confidence

St. Louis to Sofia Flights

The cheapest times to fly from St. Louis to Sofia

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

 

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

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

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 Sofia in 2026. You can also book with separate airlines for your outbound and return journeys, from $353 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 Sofia 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 Sofia 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 Sofia Flights

*Flight schedules are subject to change.

*Available to One Key members.

 

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