$352 Find Cheap Flights from Sofia to Illinois

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Sofia to Illinois departing on 2/24. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy, 0 bags

KAYAK searches hundreds of travel sites at once for deals on flights to Illinois

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Sofia to Illinois.
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Sofia to Illinois.
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Cheap Flights from Sofia to Illinois

Cheapest round-trip prices found by our users on KAYAK in the last 72 hours
Chicago
Chicago1 stop$676
St. Louis
St. Louis1 stop$750
Chicago
Chicago1 stop$676
St. Louis
St. Louis1 stop$750

Book Cheap Sofia to Illinois Plane Tickets

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Sofia to Illinois that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Sofia to Illinois

Tue, Mar 10 - Mon, Jun 15
LOT Logo
6:35 pm - 9:00 pm
SOF
-
ORD
33h 25m1 stop
LOT Logo
9:50 pm - 2:00 am
ORD
-
SOF
20h 10m1 stop
$676LOT
Sun, Jan 25 - Sun, Feb 1
LOT Logo
6:35 pm - 7:55 pm
SOF
-
ORD
33h 20m2 stops
LOT Logo
9:55 pm - 5:50 pm
ORD
-
SOF
35h 55m2 stops
$684LOT
Sun, Jan 25 - Sun, Feb 1
Air France Logo
7:00 am - 3:10 pm
SOF
-
ORD
16h 10m1 stop
Air France Logo
5:20 pm - 1:55 pm
ORD
-
SOF
12h 35m1 stop
$687Air France
Sat, May 9 - Thu, Aug 13
LOT Logo
5:20 am - 3:10 pm
SOF
-
ORD
41h 50m2 stops
LOT Logo
5:10 pm - 1:55 pm
ORD
-
SOF
36h 45m2 stops
$688LOT
Tue, Dec 23 - Mon, Jan 26
LOT Logo
6:35 pm - 8:00 pm
SOF
-
ORD
33h 25m1 stop
LOT Logo
9:55 pm - 5:50 pm
ORD
-
SOF
11h 55m1 stop
$691LOT
Thu, Jan 15 - Wed, Jan 28
Multiple Airlines Logo
5:00 am - 5:20 pm
SOF
-
ORD
20h 20m3 stops
Multiple Airlines Logo
6:30 pm - 8:50 am
ORD
-
SOF
30h 20m3 stops
$692Multiple Airlines
Thu, Feb 5 - Wed, Apr 1
KLM Logo
7:00 am - 6:49 pm
SOF
-
ORD
19h 49m2 stops
KLM Logo
4:50 pm - 2:00 pm
ORD
-
SOF
13h 10m1 stop
$696KLM
Thu, Jan 15 - Wed, Jan 28
Multiple Airlines Logo
7:00 am - 6:32 pm
SOF
-
MDW
19h 32m2 stops
Multiple Airlines Logo
1:49 pm - 2:05 pm
MDW
-
SOF
16h 16m2 stops
$696Multiple Airlines
Wed, Mar 25 - Tue, Jul 21
LOT Logo
2:35 pm - 9:00 pm
SOF
-
ORD
13h 25m1 stop
LOT Logo
9:50 pm - 1:55 pm
ORD
-
SOF
32h 05m1 stop
$697LOT
Thu, Feb 5 - Wed, Apr 1
KLM Logo
7:00 am - 5:55 pm
SOF
-
ORD
18h 55m2 stops
KLM Logo
11:15 am - 2:00 pm
ORD
-
SOF
18h 45m2 stops
$700KLM
Booking Insights

KAYAK's insights & trends for Sofia to Illinois flights

Get data-powered insights and trends into flights from Sofia to Illinois to help you find the cheapest flights, the best time to fly and much more.

What is the cheapest month to fly from Sofia to Illinois?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Sofia to Illinois, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from Sofia to Illinois is February, when tickets cost $674 (return) on average. On the other hand, the most expensive months are January and May, when the average cost of round-trip tickets is $974 and $969 respectively.

What’s the cheapest day of the week to fly from Sofia to Illinois?

The average price of all round-trip flights from Sofia to Illinois clicked on KAYAK for each day over the last 12 months.

When flying from Sofia to Illinois, you should consider leaving on a Wednesday and avoid Mondays if you are looking for the best rates. For your return to Sofia, you’ll find the best rates on Thursdays and the most expensive ones on Mondays.

How far in advance should I book a flight from Sofia to Illinois?

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from Sofia to Illinois, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below average price on the flight from Sofia to Illinois, you should book around 6 weeks before departure, which saves you about 10% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 22 weeks before departure.

Good to know

Low seasonOctober
Cheapest flight$352
Best time to beat the crowds with an average 8% drop in price.
Most popular time to fly with an average 11% increase in price.
Flight from Sofia to Chicago Midway Airport

FAQs - booking Illinois flights

  • How does KAYAK find such low prices on flights from Sofia to Illinois?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Sofia to Illinois.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Sofia to Illinois?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight from Sofia to Illinois is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Sofia to Illinois?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly from Sofia to Illinois with an airline and back with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Sofia to Illinois?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying from Sofia to Illinois up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

  • What is the cheapest time of day to fly to Illinois?

    The cheapest time of day to fly to Illinois is generally in the evening, when round-trip flights cost $666 on average. Morning departures are around 14% more expensive than evening flights, on average. The most expensive time of day to fly to Illinois is generally at night, which is peak travel time and where the average cost of a ticket is $768.

Reviews of the top 5 airlines serving from Sofia to Illinois

 
See real verified KAYAK customer reviews for airlines flying from Sofia to Illinois. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Sofia to Illinois? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
7.7
KLMOverall score based on 1432 reviews
7.2Food
8.3Crew
7.1Entertainment
7.6Comfort
7.8Boarding
Airline reviews

Terrible last row seats many seats available but no offer to move to better seat

2.0 MediocreAnonymous, Dec 2025
AMS - BUD
Read more KLM reviews

Terrible last row seats many seats available but no offer to move to better seat

Delay and had to run between flight to get my connection due to this delay but besides that the overall experience was ok. I arrived with just an hour of delay.

Flight was ok but lack of communication cost me to literally beg to be put on another flight as connecting flight had departed

They forgot to serve food and the crew was very unfriendly. Never experienced such a bad KLM flight. Usually fly from Toronto. New York was different.

Couldn’t get boarding pass in SLC even with help from a redcoat, so had to find a desk in AMS to get boarding pass. Technical problems so not sure why. Very inconvenient. The KLM app is not as user friendly as most apps. Also had to wait almost an hour on the tarmac for a fuel truck, which caused us to miss a connecting bus in LUX.

The immigration hall in Amsterdam was understaffed, so passport checking was slower than it should be for a major airport. They need to get the automatic readers up and running for non EU passport holders. Waiting in line after a long flight feels a bit abusive.

KLM remains a quality flag carrier airline which maintains its standards whilst all their competitors are lowering theirs.

The baggage drop-off in Stuttgart is bad: after online check-in you cannot use the automated baggage drop off as indicated on the website. You can use the terminals but have to cue to 1 of three open and slowly working counters to drop the bags. took about 45 minutes wait time.

My flight was delayed by 6 hours then I missed BOTH of my connecting flights, I then had to stay in the AIRPORT at JFK because soooooo many people also suffered from missing flights and there was no hotels available. I would like to be compensated for this experience! I had to stay in the airport for over 16 hours!

The service was great. However the lounge only gets passing grade

Smooth flight, excellent crew and good food. Not enough space; sitting are too small.

Flight was delayed for a hour from Warsaw, not sure why. When we landed in Chicago, plane was still on the runway for about half a hour. Took a while to get off.

No WiFi and ok comfort in business class. Home safe I guess that’s all that really matters.

Crew was excellent. Business class was poor on the short flight and mediocre at best on the international flight.

Very poor. Seats like economy class, food unbeatable, no charging, no entertainment, no WiFi, boarding by bus - no justification for calling and pricing this as business class

During the flight, the fleas biting me in the plane.

Checking in took very long for whatever reason. Flight comfort these days is always poor so… Crew was great thought!

Bags lost no more to say, bad communication and no urgency to get it back to the hotel by the airline properly the worst airline I have used.

The customer service rep on chat refused carrying golf set at no charge that is customary for LOT and others. I wanted yo carry just ONE club not even full set! Web check in was nightmare. Most horrible lounge at warsaw. To call it business class is a BIG exaggeration. Rude staff warsaw to nyc. Seats uncomfortable and not flat as is now customary. Bad content and entertainment system.

Seats were so uncomfortable, my butt hurts so much, I wish they have more cushions,it really was horrible, Except that, Stewarts were polite food was decent

It was nice to have gotten up upgraded to first class with a meal on a three hour flight

Very bad! They kept delaying my flight and wouldn’t do anything about it

Door to door, the crew and staff were amazing. It was a stressful travel day with delays, but they were focused on customers and doing what they could to get us to our destinations.

United has come a long way, it’s been a fantastic experience traveling with them.

This flight leg was fantastic - super comfortable and a great selection of things to watch on the TV. Staff were excellent, really above and beyond.

Flight was delayed only slightly before takeoff due to traffic control. However, the flight arrived early to ORD. Good flight. United has been very reliable for me.

Another delayed flight. When the delays exceed the duration of the flight, it’s a problem.

After boarding the plane in Chicago, the passengers were told that there was a technical problem with the plane. Passengers remained on the plane as they tried to fix the problem. After what was probably an hour passengers were told that there was a need to change planes as the problem was not solved. Passengers disembarked and boarded another plane. After taxing to the runway and waiting for takeoff, passengers were told that owing to the thunderstorm the flight was unable to take off but would try and reroute. After some time passengers were told there wasn't enough fuel for the new route and the plane had to return to the gate for additional fuel. after another log delay the flight got underway. On the plane there was food, drinks, ice or entertainment. We were a glass of water, which appeared rationed. Flight arrived about 5 hours late. The pilot was fantastic and communicated with the passengers throughout the ordeal.

Excellent all round, first time flying United. App is very helpful.

Efficient all round, very good crew. Short flight so the food, of course, was just snacks

Seats too much and for the price we paid eve thought economy we still had to pay $169 to check a ba that’s ridiculous and also my daughter needed water so she can take her medicine we push the boton for the attendant to get us water they never came we push it 3 times no one came and ask what we needed . Am not happy with the service at all I will not fly with TK anymore

Boarding experience was a mess- both to and from Istanbul airport. No one knew anything. They asked everyone to line up according to their sit numbers- it was unbelievable. Business class had a separate line, but it was hard to find- I had to go through all that mess before finding it. Would not recommend

Excellent food and service on my international flight. Most notable is the food provided by Turkish even for coach passengers is very good.

They can my date of travel and let me standard in Istanbul for three days stop over and only pay for one day in a hotel with only one breakfast for three days.

the flight was cancelled and I was rebooked twice, once 26 hours later, then another 24 hours later. In total the flight was delayed for 40 hours. Never again will I use kayak or Turkish Airlines for my travel.

Worst experience with boarding once we left the wheel chair even traveling business we had to wait with all the crowd for the bus to take us to the plane then climb the stairs with our bags When you pay extra for comfort and convenience and you don’t get any is disappointing

Food is very turkish. No regard for other natinalities taste and preference. The entertainment can be improved- it was the same menu on 10/8/25 and 10/25/25. The boarding is the worst in the airline industry- I suggest you ask your staff to and watch how other airlines do it.

The best airline for international travel in terms of value you get in business class (service/cost)

I liked the overall flight experience. However, Turkish officials could do a better job at guiding non-Turkish speakers to their connecting flight gates in such a huge & vast airport.

Very small and cramped aisles and seats. Food was poor but the fresh hot roll and hummus was good. No cans of soda given but they had small bottles of water. Crew was nice and pleasant and kept bathroom clean.

The seat space seemed small especially when the person ahead reclined but other than that, very good.

Luggage transfer in Chicago was not performed in time. I received my luggage at my destination two days later.

Food was poor quality and the screens for entertainment didn’t work properly

It was a short flight, everything was good with it.

I darted through the Frankfurt airport to make my connecting flight. I asked if it was a possibility to upgrade and the agent did. This was the kindest gesture and it made up for the previous delayed flight and distress/anxiety of anticipating that Zi was going to miss my Frankfurt-Chicago connection. I cannot express my gratitude for the upgrade.. I am 5feet 10 inches do the leg space was amazing.

I meant this flight was not good, the one from Tirana to Frankfurt was better!

Expect Business Class seating to be 2 passengers per 3 coach seats, with center blocked. This is typical for flights within Europe on most airlines. Service was excellent!

I was very grateful for Lufthansa's role in organizing mobility support. The touchscreen on my seat was faulty: slow, stained (I couldn't get it clean), and glitchy. This made selecting movies extremely time consuming, and twice I had to start all over from the beginning.

The crew was the best I’ve ever encountered. Business class was spacious, immaculate, and very modern.

They gave us chocolates twice (for whoever would like an extra chocolate - kids did!). I asked for an extra water, and I was given one. Crew was very friendly!

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

Information on your arrival and departure airports