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$63+ Cheap flights from San Francisco Bay Area to Illinois

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 1/29. Fares are subject to change and may not be available on all flights or dates of travel.
SFO — ORD
Dec 3 — Dec 101
Wed 12/3
Wed 12/10
1 adult, Economy
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Cheap flight deals from San Francisco Bay Area to Illinois

Keep the following information in mind while searching for San Francisco Bay Area to Illinois flight deals. Data was last updated November 3, 2025.

Most accurate provider

eDreams
3 stars

Most trusted provider

eDreams
3 stars

Round-trip from

$130
(CheapOair)

One-way from

$63
(Trip.com)

Popular in

December

Cheapest in

February

Average price

$390
Provider with most accurate pricing for San Francisco-Chicago (CHI) flight deals.
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Provider most trusted by Cheapflights users for San Francisco-Chicago (CHI) flights.
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From San Francisco Bay Area to Illinois
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One-way flight from San Francisco Bay Area to Illinois
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Highest demand for flights based on searches. 9% potential increase in price ($36 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($9 potential savings vs. average RT price).
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Average for round-trip flights in November 2025
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Find flight deals from San Francisco Bay Area to Illinois

Cheapest flights from San Francisco Bay Area to Illinois
Explore the most affordable flight options available from San Francisco Bay Area to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on November 3, 2025.

This CheapOair deal was found by Cheapflights users on 11/3. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/1712:27 pmSJC - STL
1 stop18h 40mFrontier
Thu 11/209:54 pmSTL - SJC
1 stop21h 40mFrontier
Deal found 11/3$130
This Alaska Airlines deal was found by Cheapflights users on 11/2. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/312:35 pmSJC - ORD
1 stop9h 15mAlaska Airlines
Tue 12/98:55 amORD - SJC
1 stop7h 37mAlaska Airlines
Deal found 11/2$248
This KAYAK deal was found by Cheapflights users on 11/3. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/410:28 amSJC - ORD
1 stop7h 26mAlaska Airlines
Tue 12/98:55 amORD - SJC
1 stop7h 37mAlaska Airlines
Deal found 11/3$250
This CheapOair deal was found by Cheapflights users on 11/3. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/1712:27 pmSJC - STL
1 stop18h 40mFrontier
Fri 11/2112:01 pmSTL - SJC
1 stop7h 33mFrontier
Deal found 11/3$256
This Vliegwinkel deal was found by Cheapflights users on 11/3. 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 Vliegwinkel is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/410:55 amSJC - ORD
1 stop17h 10mMultiple Airlines
Wed 12/108:55 amORD - SJC
1 stop7h 37mMultiple Airlines
Deal found 11/3$256
This KAYAK deal was found by Cheapflights users on 11/2. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/1012:35 pmSJC - ORD
1 stop9h 15mAlaska Airlines
Tue 12/168:00 amORD - SJC
1 stop9h 54mAlaska Airlines
Deal found 11/2$258
This Kiwi.com deal was found by Cheapflights users on 11/1. 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 11/138:55 pmSFO - STL
1 stop12h 29mFrontier
Sun 11/167:02 pmSTL - SFO
2 stops31h 09mFrontier
Deal found 11/1$267
This Alaska Airlines deal was found by Cheapflights users on 11/2. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/1110:28 amSJC - ORD
1 stop7h 26mAlaska Airlines
Tue 12/168:59 pmORD - SJC
1 stop16h 59mAlaska Airlines
Deal found 11/2$270
This Frontier deal was found by Cheapflights users on 10/31. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/810:23 pmSFO - STL
1 stop9h 49mFrontier
Mon 11/1012:09 pmSTL - SFO
1 stop6h 34mFrontier
Deal found 10/31$272
This Frontier deal was found by Cheapflights users on 11/2. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/138:55 pmSFO - STL
1 stop12h 29mFrontier
Wed 11/267:43 pmSTL - SFO
1 stop6h 41mFrontier
Deal found 11/2$273
This Alaska Airlines deal was found by Cheapflights users on 11/3. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/33:09 pmSJC - ORD
1 stop6h 41mAlaska Airlines
Mon 12/88:55 amORD - SJC
1 stop29h 03mAlaska Airlines
Deal found 11/3$273
This Delta deal was found by Cheapflights users on 11/3. 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.
Thu 12/117:15 amSJC - STL
2 stops9h 55mDelta
Sun 12/146:00 amSTL - SJC
2 stops11h 54mDelta
Deal found 11/3$274

Cheapflights Fare Finder

 
Customize your flight search to find flights from San Francisco Bay Area to Illinois 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 November 3, 2025.
Use the filters below to find and compare flights from San Francisco Bay Area to Illinois that are best for you.

Fly from

San Francisco Bay Area

Fly to

Illinois

Route

Depart

Return

Price

San JoseSt. Louis

SJC - STL

SJCSTL

San Jose

Mon 11/17

12:27 pm-9:07 am

1 stop18h 40m

Lambert-St Louis

Thu 11/20

9:54 pm-5:34 pm

1 stop21h 40m

$130

San FranciscoChicago

SFO - ORD

SFOORD

San Francisco

Mon 1/26

2:30 pm-11:50 pm

1 stop7h 20m

Chicago O'Hare Intl

Fri 1/30

8:00 am-2:00 pm

1 stop8h 00m

$283

OaklandChicago

OAK - ORD

OAKORD

Oakland

Wed 1/14

11:08 am-11:55 pm

1 stop10h 47m

Chicago O'Hare Intl

Thu 1/29

6:06 pm-8:40 pm

1 stop28h 34m

$283

OaklandChicago

OAK - ORD

OAKORD

Oakland

Wed 1/14

11:08 am-11:55 pm

1 stop10h 47m

Chicago O'Hare Intl

Fri 1/30

6:06 pm-4:28 pm

1 stop24h 22m

$283

San JoseChicago

SJC - ORD

SJCORD

San Jose

Mon 12/15

7:57 pm-2:09 pm

1 stop16h 12m

Chicago O'Hare Intl

Thu 12/18

8:39 am-6:46 pm

1 stop12h 07m

$290

San JoseChicago

SJC - ORD

SJCORD

San Jose

Thu 12/4

7:00 am-11:50 pm

1 stop14h 50m

Chicago O'Hare Intl

Sat 12/6

3:05 pm-9:51 am

1 stop20h 46m

$290

San FranciscoSt. Louis

SFO - STL

SFOSTL

San Francisco

Sat 12/6

10:30 am-11:27 pm

2 stops10h 57m

Lambert-St Louis

Tue 12/9

6:00 am-3:57 pm

2 stops11h 57m

$294

San FranciscoChicago

SFO - ORD

SFOORD

San Francisco

Mon 11/24

10:40 pm-5:00 am

Nonstop4h 20m

Chicago O'Hare Intl

Thu 11/27

4:17 pm-7:07 pm

Nonstop4h 50m

$297

San JoseChicago

SJC - ORD

SJCORD

San Jose

Thu 2/12

3:00 pm-1:59 pm

1 stop20h 59m

Chicago O'Hare Intl

Wed 2/18

2:59 pm-10:27 pm

1 stop9h 28m

$297

OaklandChicago

OAK - ORD

OAKORD

Oakland

Wed 1/14

10:30 am-11:55 pm

2 stops11h 25m

Chicago O'Hare Intl

Wed 1/28

6:06 pm-11:03 am

1 stop18h 57m

$298

Flights are sorted by cheapest round-trip flights first.

Deals found on 11/3

Showing 1-10 of 60 results
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Best time to book a flight from San Francisco Bay Area to Illinois

Have a flexible travel schedule? Discover the best time to fly to Illinois from San Francisco Bay Area 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 San Francisco Bay Area to Illinois

What is the cheapest month to book a flight from San Francisco Bay Area to Illinois?

Currently, December is the cheapest month in which you can book a flight from San Francisco Bay Area to Illinois (average of $111). Flying from San Francisco Bay Area to Illinois in March is currently the most expensive (average of $194). 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 XIH to IL?

Find hourly flight availability from San Francisco Bay Area to Illinois. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated November 3, 2025.

Unlike in the morning, when flights are generally more expensive, you can save up to 9% on flights from San Francisco Bay Area to Illinois by exploring options for tickets in the afternoon.

What is the cheapest day to fly from San Francisco Bay Area to Illinois?

Use this chart to determine the cheapest time to fly round-trip from San Francisco Bay Area to Illinois. Price data was last updated on December 16, 2024.

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

Weekly flight availability from San Francisco Bay Area to Illinois

Explore weekly flight availability from San Francisco Bay Area to Illinois. 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 November 3, 2025.

The most flights from zzXIH to USIL are scheduled on a Monday (70 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (31 on average).

Reviews of airlines servicing Illinois

Get insights into the airlines that provide service to Illinois. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Illinois. Reviews last updated November 3, 2025.
See what other customers who have flown with Alaska Airlines, Southwest, and United Airlines from San Francisco Bay Area to Illinois have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
11,235 reviews

Crew

8.5

Entertainment

7.0

Comfort

7.8

Overall

8.0

Food

7.1

Boarding

8.1

Reviews

1 / 20
6.0
Good

Hannah,Aug 2025

SFO - SAN

Ticket said TSA pre check, but then the TSA agent said that Alaska Airlines has not actually entered the pre check information for the ticket, so I had to use regular security. During boarding, I have a disability and need to board early. The Alaska Airlines employee announced disability boarding, but then immediately announced 2 other groups to board, so I still had to fight the crowds. On the plane, the stewardess was brusk and rude. Seats were very uncomfortable, especially on lower back.
Alaska Airlines
8.0
Very good
11,235 reviews
Alaska Airlines
8.0
Very good
11,235 reviews

Crew

8.5

Entertainment

7.0

Comfort

7.8

Overall

8.0

Food

7.1

Boarding

8.1

Reviews

1 / 20
6.0
Good

Hannah,Aug 2025

SFO - SAN

Ticket said TSA pre check, but then the TSA agent said that Alaska Airlines has not actually entered the pre check information for the ticket, so I had to use regular security. During boarding, I have a disability and need to board early. The Alaska Airlines employee announced disability boarding, but then immediately announced 2 other groups to board, so I still had to fight the crowds. On the plane, the stewardess was brusk and rude. Seats were very uncomfortable, especially on lower back.
Southwest
8.0
Very good
4,238 reviews
Alaska Airlines
8.0
Very good
11,235 reviews

Crew

8.5

Entertainment

7.0

Comfort

7.8

Overall

8.0

Food

7.1

Boarding

8.1

Reviews

1 / 20
6.0
Good

Hannah,Aug 2025

SFO - SAN

Ticket said TSA pre check, but then the TSA agent said that Alaska Airlines has not actually entered the pre check information for the ticket, so I had to use regular security. During boarding, I have a disability and need to board early. The Alaska Airlines employee announced disability boarding, but then immediately announced 2 other groups to board, so I still had to fight the crowds. On the plane, the stewardess was brusk and rude. Seats were very uncomfortable, especially on lower back.
United Airlines
7.4
Good
8,997 reviews
Alaska Airlines
8.0
Very good
11,235 reviews

Crew

8.5

Entertainment

7.0

Comfort

7.8

Overall

8.0

Food

7.1

Boarding

8.1

Reviews

1 / 20
6.0
Good

Hannah,Aug 2025

SFO - SAN

Ticket said TSA pre check, but then the TSA agent said that Alaska Airlines has not actually entered the pre check information for the ticket, so I had to use regular security. During boarding, I have a disability and need to board early. The Alaska Airlines employee announced disability boarding, but then immediately announced 2 other groups to board, so I still had to fight the crowds. On the plane, the stewardess was brusk and rude. Seats were very uncomfortable, especially on lower back.
American Airlines
7.2
Good
11,036 reviews
Alaska Airlines
8.0
Very good
11,235 reviews

Crew

8.5

Entertainment

7.0

Comfort

7.8

Overall

8.0

Food

7.1

Boarding

8.1

Reviews

1 / 20
6.0
Good

Hannah,Aug 2025

SFO - SAN

Ticket said TSA pre check, but then the TSA agent said that Alaska Airlines has not actually entered the pre check information for the ticket, so I had to use regular security. During boarding, I have a disability and need to board early. The Alaska Airlines employee announced disability boarding, but then immediately announced 2 other groups to board, so I still had to fight the crowds. On the plane, the stewardess was brusk and rude. Seats were very uncomfortable, especially on lower back.
Frontier
5.8
Fair
3,117 reviews
Alaska Airlines
8.0
Very good
11,235 reviews

Crew

8.5

Entertainment

7.0

Comfort

7.8

Overall

8.0

Food

7.1

Boarding

8.1

Reviews

1 / 20
6.0
Good

Hannah,Aug 2025

SFO - SAN

Ticket said TSA pre check, but then the TSA agent said that Alaska Airlines has not actually entered the pre check information for the ticket, so I had to use regular security. During boarding, I have a disability and need to board early. The Alaska Airlines employee announced disability boarding, but then immediately announced 2 other groups to board, so I still had to fight the crowds. On the plane, the stewardess was brusk and rude. Seats were very uncomfortable, especially on lower back.

Related info for your journey

Find useful and relevant information for your journey from San Francisco Bay Area to Illinois. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • How long is the flight from San Francisco Bay Area to Illinois?

    For as low as $283, Frontier can have you in Illinois from San Francisco Bay Area in 7h 20m. The distance from San Francisco Bay Area to Illinois is about 1841 mi. When browsing for deals, the options you’ll see will be for both nonstop flights and flights with stops.

  • What are the cheapest airlines to fly from San Francisco Bay Area to Illinois one-way?

    For one-way options, check prices for Frontier. According to our data, you can fly for as low as $114. Users have also found prices from $129 and $137 on Alaska Airlines and Delta, respectively.

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

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

  • How can I find direct flights from San Francisco Bay Area to Illinois?

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

  • Can I find deals for business class flights from San Francisco Bay Area to Illinois?

    Yes. Cheapflights offers flight deals from San Francisco Bay Area to Illinois 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 San Francisco Bay Area to Illinois?

    Currently, December is the cheapest month in which you can book a flight from San Francisco Bay Area to Illinois (average of $111). Flying from San Francisco Bay Area to Illinois in March is currently the most expensive (average of $194). 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

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Alternative routes for San Francisco Bay Area to Illinois

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

Discover the top 8 airlines that operate flights from San Francisco Bay Area to Illinois. 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 November 3, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$98Average$251FlexibilityNo cancel feeOn-time62%
Spirit AirlinesCheapest$108Average$240FlexibilityNo cancel feeOn-time65%
Hawaiian AirlinesCheapest$108Average$288FlexibilityNo cancel feeOn-time85%
DeltaCheapest$128Average$339FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$133Average$449FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$170Average$384FlexibilityNo cancel feeOn-time75%
SouthwestCheapest$185Average$423FlexibilityNo cancel feeOn-time63%
American AirlinesCheapest$197Average$525FlexibilityNo cancel feeOn-time71%

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