$69 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 8/29. 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.
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1 adult, Economy, 0 bags

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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
Chicago1 stop$265
Moline
Moline1 stop$323
Peoria
Peoria1 stop$254
Bloomington
Bloomington1 stop$379
St. Louis
St. Louis1 stop$121
Chicago
Chicago1 stop$265
Moline
Moline1 stop$323
Peoria
Peoria1 stop$254
Bloomington
Bloomington1 stop$379
St. Louis
St. Louis1 stop$121

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, Oct 27 - Sat, Oct 31
Alaska Airlines Logo
11:10 am - 11:59 pm
SAN
-
STL
10h 49m
1 stop
Alaska Airlines Logo
6:02 am - 2:38 pm
STL
-
SAN
10h 36m
1 stop
$121Alaska Airlines
Sat, Sep 12 - Tue, Sep 15
Alaska Airlines Logo
6:55 am - 5:10 pm
SAN
-
STL
8h 15m
1 stop
Alaska Airlines Logo
6:29 am - 1:21 pm
STL
-
SAN
8h 52m
1 stop
$137Alaska Airlines
Wed, Sep 9 - Sun, Sep 20
Frontier Logo
6:25 am - 7:17 pm
SAN
-
STL
10h 52m
1 stop
Frontier Logo
8:10 pm - 11:51 pm
STL
-
SAN
29h 41m
1 stop
$159Frontier
Wed, Sep 23 - Thu, Oct 15
Frontier Logo
6:25 am - 7:17 pm
SAN
-
STL
10h 52m
1 stop
Frontier Logo
8:10 pm - 11:59 pm
STL
-
SAN
29h 49m
1 stop
$164Frontier
Sat, Aug 29 - Sat, Sep 5
American Airlines Logo
7:15 am - 4:14 pm
SAN
-
STL
6h 59m
1 stop
American Airlines Logo
5:13 pm - 11:55 pm
STL
-
SAN
8h 42m
1 stop
$187American Airlines
Sat, Sep 12 - Tue, Sep 15
American Airlines Logo
8:00 am - 6:04 pm
SAN
-
STL
8h 04m
1 stop
American Airlines Logo
3:34 pm - 9:48 pm
STL
-
SAN
8h 14m
1 stop
$187American Airlines
Thu, Sep 17 - Sun, Sep 20
Multiple Airlines Logo
8:06 pm - 5:10 pm
SAN
-
STL
19h 04m
1 stop
Multiple Airlines Logo
8:10 pm - 11:51 pm
STL
-
SAN
5h 41m
1 stop
$198Multiple Airlines
Sun, Sep 13 - Wed, Sep 16
Multiple Airlines Logo
9:03 pm - 11:17 am
SAN
-
STL
12h 14m
1 stop
Multiple Airlines Logo
6:29 am - 1:21 pm
STL
-
SAN
8h 52m
1 stop
$199Multiple Airlines
Tue, Aug 25 - Wed, Aug 26
United Airlines Logo
6:20 am - 4:34 pm
SAN
-
STL
8h 14m
2 stops
United Airlines Logo
8:42 am - 1:44 pm
STL
-
SAN
7h 02m
1 stop
$253United Airlines
Sat, Oct 10 - Fri, Oct 16
United Airlines Logo
10:30 pm - 4:33 am
SAN
-
ORD
4h 03mnonstop
United Airlines Logo
4:10 pm - 6:40 pm
ORD
-
SAN
4h 30mnonstop
$267United 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.

Flight prices are typical for this route right now.

Flights to Illinois from San Diego usually cost between $250 and $379 in September.
The lowest price found in the past 5 days was $265 on Frontier (Sep 4-Sep 7).

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 $252 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 $262.

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 $337 on average. Morning departures are around 26% 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 $455.

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 $356, 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 $254 (return) on average. On the other hand, the most expensive months are July and June, when the average cost of round-trip tickets is $386 and $374 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 4 weeks before departure, which saves you about 48% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 7 weeks before departure.

Good to know

Low season

January

Cheapest flight

$69
Best time to beat the crowds with an average 7% drop in price.
Most popular time to fly and prices are also 2% lower on average.
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 $203 one-way - $338 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.
8.0
SouthwestOverall score based on 4229 reviews
8.0Comfort
8.1Boarding
8.6Crew
7.0Food
7.5Entertainment
Airline reviews

Red eye from San Diego. Temperature of the cabin was way too warm and the air duct flowed very little air.

6.0 GoodGordon, Jul 2026
SAN - MCO
Read more Southwest reviews

Red eye from San Diego. Temperature of the cabin was way too warm and the air duct flowed very little air.

Great job Southwest! My family doesn't fly often but we felt safe the whole time.

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

The charges were ridiculous for an hour flight and the turbulence was very scary.

The seats are now more narrow. I paid for front row the seats in the front are even more narrow than before.

The boarding and seat assignment system no longer works for me, but I know it is being replaced. Otherwise, I am good with the overall experience.

San Diego airport is brand new, spacious, airy and very smooth checkin at SW baggage drop.

No trays in our seats, we sat in first row, purchased a business class fare. Had to hold our drinks and snack in our hands. No plugs for our cell phones. Had to pay for it a drink cocktail each. Seats so uncomfortable.

There was over a 9 hour delay for one thing after another. A toilet problem, they had to change the brakes, they had to refuel, three pilots times out, etc. We had to sit on the plane at the gate for over 5 hours with no air.

Unfortunately it was not a good experience. There was a rude stewardess.

The flight was very late departing the gate, for unknown reasons.

Now that Spirit is not around Alaska took over the title of cheap and worse airlines with high prices for garbage cheap planes. Seats recline the entire 2”. What’s the purpose? Just make the stationary. Crew is on steroids. Food is like McDonald’s happy meal. Only happy in the name rest is garbage

Loved being about to check my carry on for free then getting to board earlier ( Group c rather than F) Crew was very nice and accommodating. Enjoyed the beverage and pretzels - I'll fly Alaska again if given the opportunity

Only issue is that when you board last they make you check your carry on due to lack of space. Did not care for that.

delay was longer than the entire flight. I didn’t stop flying with delta for this.

My flight was several times rescheduled and then finally canceled.

Worst first/business class I have ever flown after 75 years on planes. Barely acceptable seats, terrible food, uninterested attendants, unavailable WiFi. I’ll never fly this airline again.

Dropping off of the checked bags took way longer than it should have. The agent for the pre-tagged and ready to drop off line was gone and didn't come back for about 15 minutes. The other bag check lines were barely moving. Agents were standing around and not much was getting done. Everything else about the flight was great.

Check in online didn't accept my confirmation number so i could only check in with assistance at the airport and ended up with s creepy middle seat.

It was the most expensive Alaska Airlines ticket I’ve ever purchased. I had a middle seat with no legroom or space compared to any other middle seat I’ve hadThere was a silver box under the seat that took up 70% of my legroom on the most narrow 737 max the crew flat out would not help they would not help with bags they would not help with garbage there was no coffee,It was definitely not one of my better experiences on Alaska.

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

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.

Complimentary light meal would be appreciated. But great flight crew service on all legs

The food was terrible this time. Otherwise pleasant, quiet, on-time.

I was in first class. The outlets at my seat did not work. The plane was shabby and run down. I had prepurchsed a day subscription for internet that was not redeemable. I had to repurchase the internet for my flight and then it didn’t work anyway. Quite disappointed in what was supposed to be the launch of a great vacation.

As usual, United scheduling is completely misleading. A 54-minute layover at O’Hare is too short to make a lot of connections, especially since the flight landed “on time” but had to wait on the taxiway 15 minutes for a gate to open up. Then it takes another 10 minutes to exit the plane before one can run to another concourse to catch a connecting flight.

Flight was ok. Unfortunately it was a Boeing 737, which is a cramped / tight airplane. I prefer the Airbus as they are a more comfortable flight experience.

We were traveling as a family of 5 and they refused to seat us together. There were entire rows open, and my 13 year old daughter had to sit alone. Ridiculous!

Do not like the feeling of being in the basic economy. Everyone should feel good no matter what.

Well, true to American Airlines, both of my flights were delayed. But it’s a good thing that American is so consistently incompetent because if the first flight was delayed in the second flight was on time then I might’ve had a problem..

Was not able to do a online check-in because the American Airlines system doesn't store our visa or other passport information, allowing us to have a trouble-free check-in. We were forced to have to check-in at the counter which Changes are upgrade status given that we were not able to check in much earlier.

The entertainment package was vast and the selections were very current. Keep updating it was great.

The seat was so hard my tailbone was aching The crew was kind of a b**** because I made a joke that I didn't care if they close the door I total c*** when she was trying to f****** act like she was mad at me because I said that The flight was bumpy. Sure you didnt have control over that.

Cramped seats. FAA should make airlines have more legroom, for even short people complain

The plane was late and then sat on the runway for almost 45 minutes before taking off.

Had to wait on pilot and crew to depart and had to wait to arrive at the gate because they only had 2 crews working. Delays, delays....Planes just keep getting smaller and tighter and they nickle and dime for everything. When will an airline actually wake up and make flying more enjoyable?

I paid for what I got which was cheap, I brought my own entertainment. I knew what to expect, so I could be prepared. If you’re flying economy, check in early like me. I have no problems with my flight, was on time, staff were friendly, and overall good experience.

Multiple maintenance delays and the missed and rebooked connection changed gates at least 6 times including one which had us walking 20 minutes to another terminal and then back again. Seated our family of three in different middle seats throughout the plane and then there was an empty seat next to me. Very long travel day which I would have never agreed to if I knew the itinerary would be changed at 5 am, 2 hours before takeoff.

American must only test their seats on aliens. Or their goal is to become expensive Spirit.

We had an awful experience getting our bags checked in. Frontier’s check in on the app manipulated us into buying the business package because that was the only option available for a checked bag which included two checked bags per person which we did not need. Upon arriving to the airport, we stood in line for what seemed like forever at the baggage check in and there was no one available at the counter. We were first in line and we were afraid we were going to miss our flight due to the baggage attendant being late. After realizing there were a lot of other people waiting at the baggage check in and no one available. I reached out to Frontier and could not get any customer service so I had to call the airport to page the baggage attendant to send someone to the counter to check in our bags before we were able to go through security , I finally spoke to the attendant at the counter and explained to her that we had to pay for two checked bags person a total of six bags when we only had a total of three bags between three people she said to reach out to Frontier and they would issue a refund for the three bags that we paid for and did not need. I reached out to Frontier which I was not able to reach anybody by phone so I had to go through their automated chat feature, which sent me around in circles until I finally reached a representative to assist me. I explained to them what happened and they explained that they were not able to assist me. I continued to push the issue with them as this was very frustrating and they finally put in a customer service ticket where we were issued a flight credit and we were so disappointed because after this experience, we NEVER want to fly Frontier again, and we do not want a credit that we will not use. Frontier charged us almost $500 for us to check three bags which is absolutely absurd! The customer service agents were not able to offer anything else other than a flight credit and I do not feel like my frustrations were truly heard , we will never use Frontier Airlines again ! Truly Theft by Manipulation! They should be ashamed!

Every day about it was very different all the boarding pass where all wrong l miss flight no refund all crazy

The trip was good but the last minute changes I didn’t like because I had already talked to the attendee and they didn’t help me with my ticket I was having trouble checking in and when the time was up they help me but charge me for that and last minute luggage it was a small bag. After I was in the airplane I realized you were charging because the flight was almost empty and you have to get the money some how. Thanks for everything.

Our flight was delayed by four hours without notice, the app for getting my boarding pass is super confusing, and I wasn’t able to check a suitcase without paying for a higher cost package

First the gate was a total nightmare-no chairs anywhere! So over crowded and only one bathroom and nightmare of food service - took forever and NOT one place to sit. No inflight entertainment and had to pay 60.00 for a small carry on. I will never fly Frontier again!

I didn't like anything about the flight It was my first time and definitely my last time boarding a frontier flight. Their counter agents need training and they need to learn to communicate regularly and respectfully

Flight was 3 hours late leaving. Poor communication from the staff about delays. Impossible to get in touch with customer service (by design). And it actually didn't come out to be much cheaper than a non-budget airline! Not worth the headache, I'm never flying Frontier again

I did not enjoy the trip home on Frontier for several reasons: there is too much cost besides the flight, which was more than I would normally pay, then having to pay for luggage, and carry-on, seat (if you want to reserve when booking) then you must pay over $3 for a can of soda, and $4 for a snack. A cup of water is free.

Flight was delay 9hrs and nothing was provided at airport, had to go and get a room to sleep in, paid for Uber back and fort with no offers until we landed back home a 1hr later for a $75 voucher for a future flight.

Terrible. Seats are bad and the baggage policy is inconsistent

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

Information on your arrival and departure airports