HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Sofia

$258+ Cheap flights from Illinois to Sofia (SOF)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 4/21. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — SOF
Mar 19 — Mar 261
Thu 3/19
Thu 3/26
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from Illinois to Sofia with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheap flight deals from Illinois to Sofia

Cheapest flights from Illinois to Sofia
Explore the most affordable flight options available from Illinois to Sofia. Find the lowest fares from popular airlines and budget airlines, with prices last updated on February 17, 2026.

This Justfly.com deal was found by Cheapflights users on 2/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Justfly.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/223:30 pm
STL
-
SOF
1 stop13h 55m
Lufthansa
Wed 4/296:20 am
SOF
-
STL
1 stop15h 05m
Lufthansa
Deal found 2/14$528
This United Airlines deal was found by Cheapflights users on 2/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/202:40 pm
STL
-
SOF
2 stops24h 20m
United Airlines
Wed 4/296:20 am
SOF
-
STL
1 stop15h 05m
United Airlines
Deal found 2/16$538
This FlightHub deal was found by Cheapflights users on 2/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 2/238:20 pm
ORD
-
SOF
1 stop16h 30m
Turkish Airlines
Thu 3/59:40 pm
SOF
-
ORD
1 stop20h 25m
Turkish Airlines
Deal found 2/15$543
This Air France deal was found by Cheapflights users on 2/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air France is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/2111:43 am
STL
-
SOF
2 stops18h 17m
Multiple Airlines
Tue 4/287:00 am
SOF
-
STL
2 stops17h 42m
Multiple Airlines
Deal found 2/16$545
This United Airlines deal was found by Cheapflights users on 2/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/2210:00 am
STL
-
SOF
2 stops24h 40m
United Airlines
Wed 4/296:20 am
SOF
-
STL
2 stops17h 04m
United Airlines
Deal found 2/16$546
This FlightHub deal was found by Cheapflights users on 2/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/278:10 pm
ORD
-
SOF
1 stop16h 05m
Turkish Airlines
Wed 5/69:35 am
SOF
-
ORD
1 stop16h 40m
Turkish Airlines
Deal found 2/14$546
This United Airlines deal was found by Cheapflights users on 2/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/209:10 am
STL
-
SOF
2 stops25h 30m
United Airlines
Fri 5/16:10 am
SOF
-
STL
2 stops21h 54m
United Airlines
Deal found 2/16$547
This oojo deal was found by Cheapflights users on 2/17. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/68:10 pm
ORD
-
SOF
1 stop16h 05m
Turkish Airlines
Wed 5/139:35 am
SOF
-
ORD
1 stop32h 05m
Turkish Airlines
Deal found 2/17$549
This KLM deal was found by Cheapflights users on 2/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure KLM is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/2211:43 am
STL
-
SOF
2 stops18h 17m
KLM
Wed 4/297:00 am
SOF
-
STL
2 stops21h 42m
KLM
Deal found 2/14$550
This United Airlines deal was found by Cheapflights users on 2/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/223:30 pm
STL
-
SOF
1 stop18h 35m
United Airlines
Thu 4/306:30 am
SOF
-
STL
2 stops16h 54m
United Airlines
Deal found 2/16$554
This oojo deal was found by Cheapflights users on 2/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/88:10 pm
ORD
-
SOF
1 stop34h 50m
Turkish Airlines
Wed 4/229:05 pm
SOF
-
ORD
1 stop20h 35m
Turkish Airlines
Deal found 2/16$557
This United Airlines deal was found by Cheapflights users on 2/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 4/198:15 pm
STL
-
SOF
2 stops18h 45m
United Airlines
Tue 4/286:10 am
SOF
-
STL
2 stops17h 14m
United Airlines
Deal found 2/16$558

Find flight deals from Illinois to Sofia

Keep the following information in mind while searching for Illinois to Sofia flight deals. Data was last updated February 17, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$528
(Justfly.com)

One-way from

$258
(Kiwi.com)

Popular in

June

Cheapest in

February

Average price

$585
Provider with most accurate pricing for Chicago (CHI)-Sofia flight deals.
Search Deals
Provider most trusted by Cheapflights users for Chicago (CHI)-Sofia flights.
Search Deals
From Illinois to Sofia
Search Deals
One-way flight from Illinois to Sofia
Search Deals
Highest demand for flights based on searches. 26% potential increase in price ($257 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 5% potential price decrease ($37 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in February 2026
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Illinois to Sofia 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, Cheapflights users made 2,558,603 searches. Data last updated February 17, 2026.
Use the filters below to find and compare flights from Illinois to Sofia that are best for you.

Fly from

Illinois

Fly to

Sofia

Route

Depart

Return

Price

St. LouisSofia

STL - SOF

STLSOF

Lambert-St Louis

Wed 4/22

3:30 pm-1:25 pm

1 stop13h 55m

Sofia

Wed 4/29

6:20 am-1:25 pm

1 stop15h 05m

$528

St. LouisSofia

STL - SOF

STLSOF

Lambert-St Louis

Wed 4/22

10:00 am-6:40 pm

2 stops24h 40m

Sofia

Fri 5/1

6:20 am-1:25 pm

1 stop15h 05m

$538

St. LouisSofia

STL - SOF

STLSOF

Lambert-St Louis

Mon 4/20

2:40 pm-11:00 pm

2 stops24h 20m

Sofia

Wed 4/29

6:20 am-1:25 pm

1 stop15h 05m

$538

ChicagoSofia

ORD - SOF

ORDSOF

Chicago O'Hare Intl

Sun 4/5

11:25 am-8:15 pm

1 stop24h 50m

Sofia

Tue 5/5

9:35 am-9:40 am

1 stop32h 05m

$543

St. LouisSofia

STL - SOF

STLSOF

Lambert-St Louis

Wed 4/22

11:43 am-2:00 pm

2 stops18h 17m

Sofia

Wed 4/29

7:00 am-4:42 pm

2 stops17h 42m

$545

St. LouisSofia

STL - SOF

STLSOF

Lambert-St Louis

Wed 4/22

6:05 pm-11:00 pm

2 stops20h 55m

Sofia

Tue 4/28

6:10 am-3:24 pm

2 stops17h 14m

$546

St. LouisSofia

STL - SOF

STLSOF

Lambert-St Louis

Wed 4/22

6:05 pm-11:00 pm

2 stops20h 55m

Sofia

Thu 4/30

6:30 am-3:24 pm

2 stops16h 54m

$546

St. LouisSofia

STL - SOF

STLSOF

Lambert-St Louis

Sun 4/19

3:30 pm-6:10 pm

1 stop18h 40m

Sofia

Fri 5/1

6:20 am-1:25 pm

1 stop15h 05m

$546

St. LouisSofia

STL - SOF

STLSOF

Lambert-St Louis

Wed 4/22

11:43 am-2:00 pm

2 stops18h 17m

Sofia

Wed 4/29

7:00 am-8:42 pm

2 stops21h 42m

$550

ChicagoSofia

ORD - SOF

ORDSOF

Chicago O'Hare Intl

Wed 3/11

10:55 pm-5:50 pm

1 stop11h 55m

Sofia

Sat 4/11

5:20 am-3:10 pm

1 stop17h 50m

$585

Flights are sorted by cheapest round-trip flights first.

Deals found on 2/16

Showing 1-10 of 54 results
1
2
3
...
6

Best time to book a flight from Illinois to Sofia

Have a flexible travel schedule? Discover the best time to fly to Sofia from Illinois with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Illinois to Sofia

What is the cheapest month to book a flight from Illinois to Sofia?

Currently, November is the cheapest month in which you can book a flight from Illinois to Sofia (average of $472). Flying from Illinois to Sofia in June is currently the most expensive (average of $825). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

Related info for your journey

Find useful and relevant information for your journey from Illinois to Sofia. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airport do you fly into for flights to Sofia from Illinois?

    Most people fly into Sofia (SOF) if they book a flight to Sofia from Illinois. Sofia is conveniently located just 4.2 mi from Sofia’s city center.

  • How long is the flight from Illinois to Sofia?

    A quick flight from Illinois to Sofia can take about 13h 55m. Lufthansa provides one of the quickest options available for as low as $528. There are 5444 mi between Illinois and Sofia. Both multi-stop and nonstop flights can be found to your destination and back.

  • What are the cheapest airlines to fly from Illinois to Sofia one-way?

    The cheapest airlines for a one-way flight from Illinois to Sofia are Turkish Airlines ($295), United Airlines ($305), and Austrian Airlines ($330).

  • What are the most popular routes from Illinois to Sofia?

    While some choose either Chicago Midway - Sofia or Lambert-St Louis - Sofia, Chicago O'Hare Intl - Sofia is the most popular route from Illinois to Sofia.

  • Can I find deals for flights from Illinois to Sofia that include hotel bookings?

    Yes. In addition to deals on Illinois to Sofia flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Illinois to Sofia?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Illinois to Sofia.

  • Can I find deals for business class flights from Illinois to Sofia?

    Yes. Cheapflights offers flight deals from Illinois to Sofia by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Illinois to Sofia?

    Currently, November is the cheapest month in which you can book a flight from Illinois to Sofia (average of $472). Flying from Illinois to Sofia in June is currently the most expensive (average of $825). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Top 10 airlines flying from Illinois to Sofia

Discover the top 10 airlines that operate flights from Illinois to Sofia. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated February 17, 2026.
AirlineCheapestAverageFlexibilityOn-time
ITA AirwaysCheapest$469Average$965FlexibilityNo cancel feeOn-time81%
Turkish AirlinesCheapest$520Average$763FlexibilityNo cancel feeOn-time77%
KLMCheapest$533Average$654FlexibilityNo cancel feeOn-time75%
United AirlinesCheapest$566Average$787FlexibilityNo cancel feeOn-time69%
SWISSCheapest$569Average$813FlexibilityNo cancel feeOn-time79%
Air FranceCheapest$585Average$624FlexibilityNo cancel feeOn-time77%
LufthansaCheapest$587Average$876FlexibilityNo cancel feeOn-time76%
LOTCheapest$589Average$905FlexibilityNo cancel feeOn-time81%
Austrian AirlinesCheapest$606Average$966FlexibilityNo cancel feeOn-time78%
British AirwaysCheapest$609Average$749FlexibilityNo cancel feeOn-time70%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.