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$99+ Cheap flights from Illinois to San Diego (SAN)

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 8/25. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — SAN
Jul 1 — Jul 81
Wed 7/1
Wed 7/8
1 adult, Economy
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Cheap flight deals from Illinois to San Diego

Cheapest flights from Illinois to San Diego
Explore the most affordable flight options available from Illinois to San Diego. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 1, 2026.

This Southwest deal was found by Cheapflights users on 5/28. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/113:10 pm
MDW
-
SAN
1 stop5h 45m
Southwest
Sat 8/1510:40 pm
SAN
-
MDW
1 stop6h 10m
Southwest
Deal found 5/28$266
This Kiwi.com deal was found by Cheapflights users on 5/27. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/411:06 am
ORD
-
SAN
1 stop14h 53m
Frontier
Sun 11/86:25 am
SAN
-
ORD
1 stop13h 10m
Frontier
Deal found 5/27$269
This Delta deal was found by Cheapflights users on 5/29. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/259:24 am
MDW
-
SAN
1 stop6h 46m
Delta
Thu 8/2710:17 pm
SAN
-
MDW
1 stop9h 00m
Delta
Deal found 5/29$270
This Delta deal was found by Cheapflights users on 5/29. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/96:00 am
ORD
-
SAN
1 stop6h 46m
Delta
Sat 9/126:15 am
SAN
-
ORD
1 stop8h 21m
Delta
Deal found 5/29$270
This Kiwi.com deal was found by Cheapflights users on 5/31. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/248:21 pm
STL
-
SAN
2 stops21h 11m
Frontier
Wed 9/29:37 am
SAN
-
STL
1 stop7h 46m
Frontier
Deal found 5/31$271
This Kiwi.com deal was found by Cheapflights users on 5/30. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/19:48 pm
ORD
-
SAN
1 stop12h 54m
Frontier
Sun 9/66:25 am
SAN
-
ORD
1 stop12h 28m
Frontier
Deal found 5/30$274
This Southwest deal was found by Cheapflights users on 5/28. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/2210:00 am
MDW
-
SAN
Nonstop4h 10m
Southwest
Mon 8/316:45 am
SAN
-
MDW
Nonstop4h 00m
Southwest
Deal found 5/28$276
This Kiwi.com deal was found by Cheapflights users on 5/30. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/1010:40 pm
ORD
-
SAN
1 stop13h 01m
Frontier
Mon 9/1410:36 am
SAN
-
ORD
1 stop8h 59m
Frontier
Deal found 5/30$281
This Kiwi.com deal was found by Cheapflights users on 5/27. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/610:40 pm
ORD
-
SAN
1 stop19h 01m
Frontier
Tue 10/138:32 pm
SAN
-
ORD
1 stop11h 29m
Frontier
Deal found 5/27$282
This Kiwi.com deal was found by Cheapflights users on 5/31. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/210:40 pm
ORD
-
SAN
1 stop19h 01m
Frontier
Sun 10/118:32 pm
SAN
-
ORD
1 stop11h 29m
Frontier
Deal found 5/31$284
This Delta deal was found by Cheapflights users on 5/29. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/103:39 pm
STL
-
SAN
1 stop9h 21m
Delta
Fri 8/143:30 pm
SAN
-
STL
1 stop5h 56m
Delta
Deal found 5/29$284
This Kiwi.com deal was found by Cheapflights users on 5/30. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/79:13 pm
ORD
-
SAN
2 stops44h 14m
Frontier
Wed 7/153:03 pm
SAN
-
ORD
1 stop12h 34m
Frontier
Deal found 5/30$285

Find flight deals from Illinois to San Diego

Keep the following information in mind while searching for Illinois to San Diego flight deals. Data was last updated June 1, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$266
(Southwest)

One-way from

$99
(Southwest)

Popular in

March

Cheapest in

October

Average price

$347

Good round-trip deal

$347 or less

Good one-way deal

$173 or less
Provider with most accurate pricing for Chicago (CHI)-San Diego flight deals.
Search Deals
Provider most trusted by Cheapflights users for Chicago (CHI)-San Diego flights.
Search Deals
From Illinois to San Diego
Search Deals
One-way flight from Illinois to San Diego
Search Deals
Highest demand for flights based on searches. 3% potential increase in price ($9 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($7 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in June 2026
Search Deals
Price to beat on a round-trip flight from Illinois to San Diego.
Search Deals
Price to beat on a one-way flight from Illinois to San Diego.
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Illinois to San Diego 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 June 1, 2026.
Use the filters below to find and compare flights from Illinois to San Diego that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

ChicagoSan Diego

MDW - SAN

MDWSAN

Chicago Midway

Wed 8/26

8:25 pm-10:35 pm

Nonstop4h 10m

San Diego

Fri 8/28

7:55 am-5:05 pm

2 stops7h 10m

$286
Quickest round-trip

ChicagoSan Diego

MDW - SAN

MDWSAN

Chicago Midway

Wed 8/26

3:05 pm-5:10 pm

Nonstop4h 05m

San Diego

Sun 8/30

10:40 pm-4:30 am

Nonstop3h 50m

$292

St. LouisSan Diego

STL - SAN

STLSAN

Lambert-St Louis

Mon 8/3

7:45 pm-11:50 pm

1 stop6h 05m

San Diego

Sun 8/9

9:30 pm-8:08 am

1 stop8h 38m

$297

St. LouisSan Diego

STL - SAN

STLSAN

Lambert-St Louis

Mon 8/17

2:32 pm-6:06 pm

1 stop5h 34m

San Diego

Fri 8/21

5:01 pm-12:41 am

1 stop5h 40m

$297

MolineSan Diego

MLI - SAN

MLISAN

Moline Quad-City

Wed 9/9

5:00 pm-10:44 pm

1 stop7h 44m

San Diego

Sat 9/12

10:55 am-10:30 pm

1 stop9h 35m

$313

ChicagoSan Diego

ORD - SAN

ORDSAN

Chicago O'Hare Intl

Wed 6/17

6:20 am-8:54 am

Nonstop4h 34m

San Diego

Mon 6/22

5:23 pm-11:36 pm

Nonstop4h 13m

$317

ChicagoSan Diego

ORD - SAN

ORDSAN

Chicago O'Hare Intl

Sat 8/22

12:47 pm-5:46 pm

1 stop6h 59m

San Diego

Sat 9/12

10:40 pm-4:43 am

Nonstop4h 03m

$317

St. LouisSan Diego

STL - SAN

STLSAN

Lambert-St Louis

Fri 7/17

5:59 pm-10:34 pm

1 stop6h 35m

San Diego

Wed 7/22

4:07 pm-11:57 pm

1 stop5h 50m

$317

PeoriaSan Diego

PIA - SAN

PIASAN

Greater Peoria

Tue 7/7

6:58 pm-11:26 pm

1 stop6h 28m

San Diego

Sat 7/11

3:08 pm-11:40 pm

1 stop6h 32m

$321

ChicagoSan Diego

ORD - SAN

ORDSAN

Chicago O'Hare Intl

Thu 6/18

6:00 am-10:08 am

1 stop6h 08m

San Diego

Sun 6/21

10:40 pm-4:49 am

Nonstop4h 09m

$327

Flights are sorted by cheapest round-trip flights first.

Deals found on 5/29

Showing 1-10 of 60 resultsSorted by cheapest first
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Best time to book a flight from Illinois to San Diego

Have a flexible travel schedule? Discover the best time to fly to San Diego 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 San Diego

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

Currently, February is the cheapest month in which you can book a flight from Illinois to San Diego (average of $227). Flying from Illinois to San Diego in March is currently the most expensive (average of $405). 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.

What is the cheapest time of day to fly from IL to SAN?

Find hourly flight availability from Illinois to San Diego. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated June 1, 2026.

A simple way to save on the total cost of your ticket is to fly from Illinois to San Diego in the evening. If you’re flexible enough to do this you can expect to save up to 17% on your trip compared to booking a flight in the morning.

Weekly flight availability from Illinois to San Diego

Explore weekly flight availability from Illinois to San Diego. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated June 1, 2026.

The most flights from USIL to SAN are scheduled on a Monday (52 on average). You will have fewer flight options on Thursday, which is when the least amount of flights are scheduled (23 on average).

How much does it cost to fly round-trip from Illinois to San Diego?

How far ahead should I book a flight from Illinois to San Diego?

To ensure you get the cheapest price possible for a flight from Illinois to San Diego, you should look to book at least 45 days in advance of your intended travel date. The price of your flight may increase if you delay and leave booking until a week or so before departure.

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

Use this chart to determine the cheapest time to fly round-trip from Illinois to San Diego. Price data was last updated on May 30, 2026.

Travelers seeking maximum savings on their Illinois to San Diego flight should consider departing on Saturday afternoons when fares are most often at their lowest. Monday mornings flights should be avoided if possible as fares are typically the most expensive at this time.

Related info for your journey

Find useful and relevant information for your journey from Illinois to San Diego. 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 San Diego from Illinois?

    Most people fly into San Diego (SAN) if they book a flight to San Diego from Illinois. San Diego is conveniently located just 2.6 mi from San Diego’s city center.

  • How long is the flight from Illinois to San Diego?

    For as low as $286, Southwest can have you in San Diego from Illinois in 4h 10m. Illinois and San Diego are separated by a distance of 1725 mi. Both multi-stop and nonstop flights can be found to your destination and back.

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

    To fly one-way, consider booking your trip with Frontier, which is currently one of the cheapest options available, starting at $57. Hawaiian Airlines flights start at $69 while deals on Southwest start at $76 one-way.

  • What are the most popular routes from Illinois to San Diego?

    Most travelers choose Chicago O'Hare Intl - San Diego, Chicago Midway - San Diego or Lambert-St Louis - San Diego when deciding on the best route from Illinois to San Diego.

  • What are the most reliable airlines from Illinois to San Diego?

    Consider Air Canada (79%), United Airlines (79%) or Alaska Airlines (79%) when booking your flight. These represent the most reliable airlines when flying from Illinois to San Diego.

  • What are the cheapest flights from Illinois to San Diego?

    The cheapest flight price from Illinois to San Diego is $128. On average you can expect to pay $706. The most popular route, (Chicago O'Hare Intl - San Diego), can usually be booked for $270.

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

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

  • How can I find direct flights from Illinois to San Diego?

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

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

    Yes. Cheapflights offers flight deals from Illinois to San Diego 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 San Diego?

    Currently, February is the cheapest month in which you can book a flight from Illinois to San Diego (average of $227). Flying from Illinois to San Diego in March is currently the most expensive (average of $405). 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

Traveling to a place near San Diego?

Book flights to San Diego if you plan to visit one of these locations
El Cajon
Chula Vista
National City
Coronado
Poway
La Mesa
Julian
Santee
Lemon Grove

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Alternative routes for Illinois to San Diego

See prices for flight routes from nearby airports that may be better suited for you.
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Top 8 airlines flying from Illinois to San Diego

Discover the top 8 airlines that operate flights from Illinois to San Diego. 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 June 1, 2026.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$96Average$275FlexibilityNo cancel feeOn-time62%
Hawaiian AirlinesCheapest$138Average$237FlexibilityNo cancel feeOn-time85%
Alaska AirlinesCheapest$148Average$291FlexibilityNo cancel feeOn-time75%
American AirlinesCheapest$156Average$441FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$157Average$391FlexibilityNo cancel feeOn-time69%
JetBlueCheapest$167Average$376FlexibilityNo cancel feeOn-time62%
SouthwestCheapest$177Average$342FlexibilityNo cancel feeOn-time63%
DeltaCheapest$186Average$324FlexibilityNo cancel feeOn-timeN/A

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