$86 Find Cheap Flights from San Diego to Illinois - Compare and Save

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

Cheapest round-trip prices found by our users on KAYAK in the last 72 hours
Chicago
Chicagononstop$286
Moline
Moline1 stop$313
Peoria
Peoria1 stop$321
Bloomington
Bloomington1 stop$417
St. Louis
St. Louis2 stops$249
Chicago
Chicagononstop$286
Moline
Moline1 stop$313
Peoria
Peoria1 stop$321
Bloomington
Bloomington1 stop$417
St. Louis
St. Louis2 stops$249

Book Cheap San Diego 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 Diego 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 Diego to Illinois

Tue, Jul 21 - Thu, Jul 23
Frontier Logo
4:12 pm - 6:05 pm
SAN
-
STL
23h 53m
2 stops
Frontier Logo
7:10 pm - 8:06 pm
STL
-
SAN
26h 56m
1 stop
$249Frontier
Tue, Jul 21 - Thu, Jul 30
Frontier Logo
4:12 pm - 6:05 pm
SAN
-
STL
23h 53m
2 stops
Frontier Logo
7:10 pm - 8:06 pm
STL
-
SAN
26h 56m
1 stop
$250Frontier
Wed, Sep 9 - Sun, Sep 13
Alaska Airlines Logo
1:03 pm - 7:21 pm
SAN
-
ORD
4h 18mnonstop
Alaska Airlines Logo
6:00 am - 1:21 pm
ORD
-
SAN
9h 21m
1 stop
$286Alaska Airlines
Sun, Dec 13 - Thu, Jan 7
Alaska Airlines Logo
5:49 pm - 11:59 pm
SAN
-
ORD
4h 10mnonstop
Alaska Airlines Logo
7:55 pm - 10:15 pm
ORD
-
SAN
4h 20mnonstop
$292Alaska Airlines
Thu, Aug 6 - Wed, Aug 12
Southwest Logo
5:50 pm - 11:45 pm
SAN
-
MDW
3h 55mnonstop
Southwest Logo
3:05 pm - 5:10 pm
MDW
-
SAN
4h 05mnonstop
$292Southwest
Sat, Sep 5 - Thu, Sep 10
Southwest Logo
6:15 pm - 5:00 am
SAN
-
MDW
8h 45m
1 stop
Southwest Logo
5:30 am - 9:55 am
MDW
-
SAN
6h 25m
1 stop
$295Southwest
Sat, Jul 25 - Sat, Aug 8
American Airlines Logo
1:07 pm - 12:41 am
SAN
-
MLI
9h 34m
1 stop
American Airlines Logo
7:22 pm - 11:55 pm
MLI
-
SAN
6h 33m
1 stop
$313American Airlines
Tue, Aug 18 - Sat, Aug 22
American Airlines Logo
9:48 am - 6:15 pm
SAN
-
PIA
6h 27m
1 stop
American Airlines Logo
3:02 pm - 9:22 pm
PIA
-
SAN
8h 20m
1 stop
$321American Airlines
Tue, Aug 18 - Sat, Aug 22
United Airlines Logo
6:40 am - 3:00 pm
SAN
-
PIA
6h 20m
1 stop
United Airlines Logo
10:41 am - 5:26 pm
PIA
-
SAN
8h 45m
2 stops
$326United Airlines
Wed, Aug 26 - Sat, Aug 29
United Airlines Logo
9:45 pm - 12:22 pm
SAN
-
MLI
12h 37m
2 stops
United Airlines Logo
8:13 am - 3:02 pm
MLI
-
SAN
8h 49m
1 stop
$418United Airlines
Booking Insights

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

Get data-powered insights and trends into flights from San Diego 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 Diego 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 Diego to Illinois departing in September.

What is the cheapest San Diego 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 Diego found in the last 5 days was to Chicago, at $307 round-trip. The most popular route is from San Diego (SAN) to Chicago O'Hare Intl Airport (ORD), and the cheapest round-trip airline ticket found on this route in the last 5 days was $307.

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

The average price for all round-trip flights from San Diego 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 in the evening, when round-trip flights cost $304 on average. Morning departures are around 39% 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 $450.

Can I save money by flying with a layover from San Diego 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 $396, prices are generally cheapest when you fly direct.

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

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from San Diego 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 Diego to Illinois is February, when tickets cost $91 (return) on average. On the other hand, the most expensive months are April and December, when the average cost of round-trip tickets is $740 and $537 respectively.

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

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

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

How far in advance should I book a flight from San Diego 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 Diego 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 Diego to Illinois, you should book around 3 weeks before departure, which saves you about 38% 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
Cheapest flight$86
Best time to beat the crowds with an average 3% drop in price.
Most popular time to fly with an average 6% increase in price.
Flight from San Diego to St. Louis

Flights from San Diego to Illinois: the best tips from KAYAK users

Insights shared by verified travelers who flew the route from San Diego to Illinois 
CupcakeFlew with Alaska Airlines
SAN
-
ORD
Apr 2026
Please bring a water bottle for hydration during the flight.
RodFlew with United Airlines
SAN
-
ORD
Sep 2024
Yes! Don’t reserve a flight with less than 1 1/2 hour connection time or you have a good possibility of missing your connection.

FAQs - booking Illinois flights

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

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

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight from San Diego 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 Diego 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 Diego 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 Diego 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 Diego 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 Diego to the following destinations at these prices or less: Chicago $185 one-way - $361 round-trip

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

 
See real verified KAYAK customer reviews for airlines flying from San Diego 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 Diego 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.
7.9
Alaska AirlinesOverall score based on 12521 reviews
7.1Food
8.1Boarding
7.0Entertainment
7.8Comfort
8.5Crew
Airline reviews

My flight was several times rescheduled and then finally canceled.

2.0 MediocrePeter, Jun 2026
SAN - ORD
Read more Alaska Airlines reviews

My flight was several times rescheduled and then finally canceled.

Short trip, was nice to have a drink on the short flight still.

Flight got delayed like 5 times, then they put and ada passenger in the back of the plane.

Flight delayed no communication. The gate was changed so many times.

Alaska is by far the best airline to fly with 😍

More efficient with checking lines and boarding/checking bags when needed.

They were really helpful with every question and my kids had never been on a plane and the staff made them feel comfortable

I was on flight #3022 departed from San Diego, California to Medford, Oregon. I had Denise & Damaris as my flight attendants. I didn’t have much interaction with Damaris, but I did with Denise who had, this calm, cool collective voice when she spoke about the emergency exit plans before takeoff. I travel often and I’ve never met a flight attendant that can put you at ease. I felt she respects and takes pride in her position and more airlines need to adopt the integrity and respect that she has for Alaska Airlines. Debbie

All airlines should board planes back to front, instead of catering to higher priced tickets. The boarding groups are inefficient and delay takeoff time

Luggage was severely damaged. Flight was late for several hours

Flight was delayed over 3 hours. Planes were dirty. Staff indifferent. And they serve vegan pretzels as snacks.

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.

Service was professional and quick. Premium economy seat was comfortable given the class

Over 5 hour delay with minimal updates or ability to standby for alternative flights. During boarding and 1 hr+ wait for takeoff, seats were drenched w water from air conditioning condensation and always leftover crumbs on carpet and seats

The staff was extremely helpful and friendly at all times! They went above and beyond to get us into an earlier flight in San Diego to make our connection in SFO possible, because our original flight did actually not make it! I did so much appreciate the UA team and how they made this possible. We also didn’t have seats together on the long flight to Singapore, but they found us seats together last moment with no additional cost! Nobody sat next to us, so that we were able to sleep! Thanks to UA for improving their service and Underpricer for booking this trip! Please be careful: 1,5 hrs for transfer in San Francisco might not be enough time in the future

Over 2.5 hour maintenance delay on first morning flight with no acknowledgement, compensation or even gesture of good will. Aircraft had overnighted at airport so issue should have been addressed prior to boarding. Over 3.5 hours before first slow and deliberate beverage service.

Boarded early, left early, arrived 40 mins early! A win win for me!

These airplanes should be illegal. The seats are two tight, it is a safety issue. Wheelchair support was ridiculously slow. We almost missed our flight.

This flight is a quick way to get to Chicago, but a bit expensive.

O’hsre taxi and deboarding took 40 minutes. Needed 20 minutes extra time between connecting flights to avoid running through terminal.

Standard flight with a drinks and a snack- overall very quick flight. The flight attendants were very strict, bordered on rude.

Delayed - weather wasn't bad at either end. Also sat on tarmac in ORD.

The flight was delayed significantly and we sat on runway after landing for awhile. Best thing was the flight attendant, Jenny, in first class, who was very professional and attentive. She was excellent - the rest of the flight was not.

The flight attendants were extremely sourly and borderline rude. I did not feel appreciated as an AA customer once.

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

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.

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.

Very good I can’t complain one bit. Thank you American Airlines for making my flight enjoyable and safe!

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 Diego to Illinois

Information on your arrival and departure airports