$141 Find Cheap Flights from San Francisco 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 San Francisco to Illinois departing on 7/20. 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 San Francisco to Illinois.
These are the airlines KAYAK users have selected most often from within our search results in flight searches from San Francisco to Illinois.
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Cheap Flights from San Francisco to Illinois

Cheapest round-trip prices found by our users on KAYAK in the last 72 hours
Chicago
Chicago1 stop$307
Moline
Moline1 stop$340
Peoria
Peoria1 stop$340
Bloomington
Bloomington1 stop$429
Champaign
Champaign1 stop$464
Springfield
Springfield1 stop$525
St. Louis
St. Louis1 stop$353
Decatur
Decatur1 stop$444
Paducah
Paducah1 stop$438
Chicago
Chicago1 stop$307
Moline
Moline1 stop$340
Peoria
Peoria1 stop$340
Bloomington
Bloomington1 stop$429
Champaign
Champaign1 stop$464
Springfield
Springfield1 stop$525
St. Louis
St. Louis1 stop$353
Decatur
Decatur1 stop$444
Paducah
Paducah1 stop$438

Book Cheap San Francisco 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 San Francisco 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 San Francisco to Illinois

Wed, Jun 24 - Tue, Jun 30
Frontier Logo
10:58 pm - 5:07 am
SFO
-
ORD
28h 09m
1 stop
Frontier Logo
6:55 am - 7:55 pm
ORD
-
SFO
15h 00m
1 stop
$307Frontier
Tue, Sep 1 - Fri, Sep 4
Southwest Logo
6:35 am - 4:00 pm
SFO
-
MDW
7h 25m
2 stops
Southwest Logo
12:05 pm - 5:35 pm
MDW
-
SFO
7h 30m
1 stop
$308Southwest
Mon, Jun 22 - Sat, Jun 27
Frontier Logo
8:45 pm - 5:07 am
SFO
-
ORD
6h 22m
1 stop
Frontier Logo
7:20 am - 2:16 pm
ORD
-
SFO
8h 56m
1 stop
$308Frontier
Thu, Sep 10 - Mon, Sep 28
United Airlines Logo
12:35 am - 6:56 am
SFO
-
ORD
4h 21mnonstop
United Airlines Logo
9:40 pm - 12:30 am
ORD
-
SFO
4h 50mnonstop
$311United Airlines
Thu, Aug 27 - Mon, Aug 31
American Airlines Logo
7:00 am - 5:47 pm
SFO
-
ORD
8h 47m
1 stop
American Airlines Logo
7:22 am - 10:00 am
ORD
-
SFO
4h 38mnonstop
$312American Airlines
Fri, Jul 17 - Tue, Jul 21
American Airlines Logo
8:11 pm - 5:00 am
SFO
-
ORD
6h 49m
1 stop
American Airlines Logo
6:29 am - 9:05 am
ORD
-
SFO
4h 36mnonstop
$313American Airlines
Mon, Jul 6 - Sat, Jul 18
Delta Logo
12:35 am - 8:37 am
SFO
-
MDW
6h 02m
1 stop
Delta Logo
9:54 am - 4:25 pm
MDW
-
SFO
8h 31m
1 stop
$314Delta
Sat, Jul 4 - Tue, Jul 14
Delta Logo
5:55 am - 4:45 pm
SFO
-
ORD
8h 50m
1 stop
Delta Logo
7:29 am - 1:26 pm
ORD
-
SFO
7h 57m
1 stop
$314Delta
Sat, Jul 11 - Thu, Jul 30
Alaska Airlines Logo
7:55 am - 7:37 pm
SFO
-
ORD
9h 42m
1 stop
Alaska Airlines Logo
6:20 am - 11:49 am
ORD
-
SFO
7h 29m
1 stop
$315Alaska Airlines
Mon, Jun 29 - Tue, Jul 7
United Airlines Logo
12:45 am - 10:07 am
SFO
-
STL
7h 22m
1 stop
United Airlines Logo
7:23 pm - 9:43 pm
STL
-
SFO
4h 20mnonstop
$371United Airlines
Booking Insights

KAYAK's insights & trends for San Francisco to Illinois flights

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

How much is a round-trip flight from San Francisco to Illinois?

This analysis is based on the cheapest round-trip price found on KAYAK in the last 12 months by searching for a flight from San Francisco to Illinois departing in June.

What is the cheapest San Francisco to Illinois flight route?

Data is based on round-trip flight searches on KAYAK over the past month.

The cheapest ticket to Illinois from San Francisco found in the last 5 days was to Chicago, at $304 round-trip. The most popular route is from San Francisco (SFO) to Chicago O'Hare Intl Airport (ORD), and the cheapest round-trip airline ticket found on this route in the last 5 days was $304.

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

The average price for all round-trip flights from San Francisco to Illinois depending on the time of departure, clicked by users on KAYAK in the last 2 weeks.

The cheapest time of day to fly to Illinois is generally at night, when round-trip flights cost $447 on average. Morning departures are around 2% more expensive than evening flights, on average. The most expensive time of day to fly to Illinois is generally in the afternoon, which is peak travel time and where the average cost of a ticket is $487.

Can I save money by flying with a layover from San Francisco to Illinois?

The average round-trip price for all non-stop flights, flights with one layover, and flights with two layovers for the route found by users searching on KAYAK in the last 2 weeks.

No, with an average price for the route of $440, prices are generally cheapest when you fly direct.

What is the cheapest month to fly from San Francisco to Illinois?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from San Francisco 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 San Francisco to Illinois is September, when tickets cost $289 (return) on average. On the other hand, the most expensive months are January and February, when the average cost of round-trip tickets is $1,050 and $802 respectively.

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

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

If your flying dates are flexible, you should consider flying to Illinois on a Wednesday, as we generally find the cheapest rates on that day for this route. On the other hand, Sunday is the most expensive day to fly from San Francisco to Illinois. For your return ticket, we recommend flying on a Thursday and avoiding Sundays for the best deals.

How far in advance should I book a flight from San Francisco 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 San Francisco 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 San Francisco to Illinois, you should book around 4 weeks before departure, which saves you about 42% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 7 weeks before departure.

Good to know

Low seasonJanuary
Best time to beat the crowds with an average 5% drop in price.
Most popular time to fly with an average 1% increase in price.

FAQs - booking Illinois flights

  • How does KAYAK find such low prices on flights from San Francisco 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 San Francisco to Illinois.

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

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight from San Francisco 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 San Francisco 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 San Francisco 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 San Francisco 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 San Francisco to Illinois up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Top tips for finding cheap flights to Illinois

  • Looking for a cheap flight? 25% of our users found tickets from San Francisco to the following destinations at these prices or less: Chicago $221 one-way - $417 round-trip

Reviews of the top 5 airlines serving from San Francisco to Illinois

 
See real verified KAYAK customer reviews for airlines flying from San Francisco 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 San Francisco 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.
8.0
SouthwestOverall score based on 4256 reviews
8.1Boarding
8.0Comfort
7.5Entertainment
7.0Food
8.6Crew
Airline reviews

Was fine, delayed and feels like southwest is always late

6.0 GoodAnonymous, Jun 2026
SMF - LAS
Read more Southwest reviews

Was fine, delayed and feels like southwest is always late

The flight was smooth. The Southwest experience has degraded overall, but this one was okay.

The checking experience in Orlando was terrible, almost missed the flight. Too many travelers and Southwest completely understaffed.

The entire experience from boarding to landing was amazing! The crew were very friendly. Will definitely be back.

no service at all due to turbulence. they should've at least given us snacks, there were only 10 people on the entire flight.

Delayed flight, lack of information, boarding process is a mess as is the carryon luggage causing issues when leaving the plane….just a poor experience.

Comfortable. Easy. No problems. Just wish they had gf options for snacks.

The crew was very kind and made going to Hawaii relaxing and fun to look forward to! Thank you Southwest for a pleasant flight!

For the first time in a long time, the Wi-Fi actually worked the entire flight! The flight crew was amazing as usual.

Great flight. I didn't get a drink because I was asleep whole on the flight.

They called me 2 hours before my original flight from SFO was to depart to let me know it was delayed and that I would miss my connection. They then rebooked on a different flight leaving a half hour earlier to a different connecting airport, so that I would not miss my connection. It all worked out and I arrived at my destination without a problem and 15 minutes earlier than the original flight would have. Nice!

The flight would have been very good , if not dor the constantly screaming baby in the row behind me. Is there a way to isolate people traveling with infants? This is not the first time this has happened to me.

They treat me well because of my one world status. Crew is attentive and professional. One of the best airlines out there.

Crew were bad Didn’t help with luggage When asked for a glass of wine, I was told that they will serve later , which they didn’t to Me and didn’t serve anyone else in First class . Didn’t offer any snacks , Chips or Nuts to anyone . Flight was not crowded either. Worst Service/ or No Service !

Alaska drastically changed our flight from a direct flight to a flight with connection and a long layover. So we canceled the Alaska flight and we learned a valuable lesson that we will never book through kayak again because the third party travel agent tried to withhold our money.

Four hour delay. Missed our event. And they offered me $75. Absolutely shameful.

I have been flying commercial for decades. I was in one of the ladder boarding groups, had my bag tagged because they thought there was not going to be enough space for it in the overhead bins. I politely asked one of the attendance if I could try to find a space- she said I could and I did. I then took the bag tag off and gave it to one of the other attendants as I was told to do by the first one. He, in a curt, anal, and disrespectful manner, told me that I needed to take my bag down from the overhead bin and check it. This was a situation I’ve never encountered before. The attendant’s attitude was confrontational and belittling in front of other onlooking passengers as if daring me to challenge him. I am a physician who takes care of patients day in and day out. Not wanting to make a scene, I calmly told him, “do what you need to do.” he took my bag down from the overhead bin, put the back tag back on it, and checked it only to make room for another bag that was also supposed to be technically checked by a following passenger. The same male attendant later came up to me and said “you shouldn’t have showed me the bag tag,” as if conveying that he was just following protocol was a justification for treating me like a kid out of line. I cared about this because it took 15 minutes from my life to then retrieve the bag at baggage claim and it also felt like really poor customer service. I understand the need for protocols. This is also a service industry, and we the passengers are the clients. We should be made to feel welcome and respected and our life in transit made as easy as it can be within reason. This attendant clearly needs to be reminded of that. Of note, an older female fellow passenger sitting next to me agreed with this assessment.

Nice crew, healthy snacks and drinks available. Flight to Seattle was short and comfortable.

had to be rerouted due to a medical emergency onboard. Alaska crew treated the patient with utmost respect and continued to keep the passengers updated the entire way through, which I appreciate. But it took 4 hours from landing until we were able to be airborne again, causing us to not get into SFO until ~2 am. I understand it was a tough situation for everyone, but that was an indecent wait.

I love Alaska! We arrived on the later side without seat assignments only to find the had oversold the flight by 1. The attendants worked extra hard to find a way for our party of 7 to stay together and we made it on the flight! Loved the free WiFi also!

Horrifying Almost 2 million miles. Bring your own food and drink. One coffee or drink every three hours. Have to order meals on app more than 24 hours ahead Tiny and dirty bathrooms

My service dog and I were asked to deplane just before they closed the door - clearly very last minute they couldn’t find the documentation that I have filled out many many times before that is for flying service animals. I purposely purchase 3seats (a whole row) since he is large and not all passengers want to sit next to a dog on a cross country flight. The plane departed with my husband on it!!! They made me fill out a hard copy of the same form and had to reschedule me on a later flight where they could find 3 seats together!! I’ve done this so many times before - clearly the error was on their part in a technology glitch - but really people - do better!! Very traumatic - and my husband had to wait for us when he landed ….so bad. Poor pup was confused and tired.

No screens or meal options. Freezing cold. Dirty seats. Left late.

Outstanding service, efficient & friendly crew, flight was safe, comfortable & on time

It was a red-eye, but the flight felt surprisingly quick. The seats were very comfortable, and that made resting much easier. I also want to thank the gentleman seated next to me, who graciously moved so my mom could sit beside me. We slept almost the entire way. The cabin crew was respectful in not disturbing us, while also being courteous and professional throughout. Thank you, United.

Boarding was again a "free for all". We were boarding group 4, and almost the entire plane was able to board before us. It's a shame that someone who follows the rules, gets the short end of the stick. Not fair.

It was perfect! I've never flown with United before, but I definitely will in the future

They delayed the flight from 9:00 to 11:55 At 11:45 they canceled the flight. I paid a premium price for the tickets with poor service

Seats are uncomfortable. This has been a trend in the industry for decades. Trying to fit more seats on each plane to increase profits at the expense of the passenger.

Staff were good. My seat was in need of repair, but for a short flight was not problematic. Usual basic snack and drink setup that you'll find on any US carrier. Over, a decent, basic flight.

The flight from LA to Chicago was smooth and service was very good overall.

The Mario was so helpful and provided amazing customer service however l have being waiting for a callback for almost a week now and have not heard anything further after l informed them l wanted to change my date of traveling because of my hospital appointment even send them proof and l was unable to use manag your booking on their website is a bit frustrating and l would appreciate an update on My request as soon as possible. And have called them times without numbers no response

B-class on an old plane with antiquated amenities and poor service. Landed in Rome w/o bag that didn’t make the connection (plenty of time in London). Bag will come to hotel NOT the day it lands but the following night!! Still waiting for bag…BA had nothing to offer in support and couldn’t even tell me their comp, told to submit receipts and then I’ll learn what is or isn’t covered.

Awful, tons of delays, I got into Chicago multiple hours late meaning I hit the very traffic I tried so desperately to avoid. Just empty apologies from American Airlines text alerts. Trash behavior from a trash airline.

They lost my baggage and I am still struggling to the information and update

Requested early boarding to disinfect seat, tray table, etc. before general boarding. Instructed to board after wheelchair passengers. Waited on jet bridge behind 12 wheelchair passengers. Stopped immediately after entering plane to wait for gate agent in rear of plane cleaning a seat that was wet, got to my row and found both seats adjacent to mine already occupied, with the lack of room making it impossible for me to clean my own space and defeating the purpose of my boarding early. Cleaned the armrests and tray table as best I could.

The wifi experience is awful. I had to try again and again, taking over 30 minutes, to connect to the wifi. I had to watch the same two ads over and over until I was finally successful. Once connected, it was anything but "high speed" and disconnected at least three times during the flight.

Premium Economy Good crew, good service, excellent food. Seat back screen just not bright enough.

It was good, the staff was great, and the food, was as usual, tea and biscuit. Bathroom was clean, and the plane was clean as well.

The SFO Lounge crew were amazing. The bartender Faris was great. Thanks!

Flight was scheduled at 9:40pm. Got delayed to 10 am, the next day. crazy

The bag check, flight check-in, and onboard experience convinced my wife and me that we will actively go out of our way to avoid flying Frontier Airlines in the future. At bag check, we were informed that check-in could only be completed via the Frontier mobile app. Unfortunately, the app was extremely frustrating—sending us through repetitive, confusing loops that repeatedly forced us to decline add-on services with nearly every click. While most airline apps upsell, this one felt intentionally exhausting. As the process dragged on, we became genuinely concerned that my phone battery would die before check-in could be completed. We approached the bag check staff—who were standing together talking—and explained both our frustration and our predicament. They laughed. Later, my wife described the interaction as “gaslighting,” which felt accurate. We were then informed it would cost $25 per person simply to have our boarding passes printed. From that point forward, the tone of the experience was consistently hostile. The bag check employees were condescending and combative, behaving more like bullies than customer service staff. Unfortunately, that same attitude continued onboard. One flight attendant argued with me when I attempted to stow my backpack in the overhead bin. I explained that we had each paid $75 to check our bags specifically so we would not need to use carry-on space and could have adequate legroom. She demanded to see my ticket, pointed out that it said “no carry-on”—which I acknowledged—and I reiterated that this was precisely why we paid to check our bags. Her response was, “I don’t make the rules.” She then walked away, but not before asking if I “truly wanted to fly back to Chicago today?”—an unnecessary and unmistakable threat. It is also worth noting that despite booking our tickets together in the same transaction, we were not seated together. Upon our return to Chicago—where we could once again sit together—we compared onboard experiences. We both remarked on how unhappy the flight attendants appeared and how each of us was separately asked whether we would like to purchase a beverage. We declined. At no point was water mentioned as an option, leaving us with the clear impression that even water came at a cost—or that complimentary water, if available at all, was deliberately left unmentioned. Overall, the experience was shocking and deeply disappointing, but it was also a profound learning experience—one we will not forget and will not repeat. -Steve

They didn’t offer a water, even after I asked

Remind customers of the need to have passport or new ID for boarding.

The flight never took off and we spent 7 hours at the airport

Good for a budget airline! It was easy to get on, staff was really nice. Can’t say anything about the food or entertainment because it wasn’t available, which is fine.

It was ok. It was expensive to check 2 bags ($75.00 per bag), and then it took a long time to wait for shuttle to take us from one terminal to the terminal where the plane was taking off at LAX. And all of this for a flight where we had to pay for any food or drink that was not water.

This company socks. It's fraud. They canceled our flight yesterday, and today we were late because of a really long line at the check in bag. At the rebook station, there was ton of people. The workers were all rude. I am gonna make a report to FTC.

When I wanted to check in 3 hours prior to boarding time, the employees mentioned “a little over an hour delay” so I waited for an hour then I went to go look for food in the terminal and most people from that flight were in the same area looking for food. Finally I decided after food to check to see if it’s anytime closer and now it’s 2 mins until boarding closes?! What are you kidding me? I didn’t receive anything via sms about boarding now nor via email or on the intercom. I luckily made it through, barely, and then there’s no room for my carry on mind you I’m in the very first row so I had to place my purse in one further row back and my carry on sections down. Not sure who pays for better seats to get your stuff placed all over the plane but that was the worst experience I’ve ever had flying with anyone.

The single worst check in experience I could imagine. I’ll never do any business with Frontier or any affiliated company

Everything you need to know for your flight from San Francisco to Illinois

Information on your arrival and departure airports