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Cheap flights from Ontario to San Francisco from C$ 131

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 18/3. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — SFO
25 Feb — 4 Mar1
1 adult
1 adult, Economy, 0 bags
Cheapflights Tip: The best prices from Ontario to San Francisco are usually found in May or April, booked 37 days in advance, depart on a Monday or Wednesday and return on a Monday

Cheap flight deals from Ontario to San Francisco

Enter your travel dates to find the best prices.

Cheapest flights from Ontario to San Francisco
Explore the most affordable flight options available from Ontario to San Francisco. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 26 January 2026.

Thu 16/49:02 a.m.
ONT
-
SFO
Nonstop1h 35m
Frontier
Sun 19/49:23 a.m.
SFO
-
ONT
Nonstop1h 29m
Frontier
Deal found 25/1C$ 193
Mon 23/29:06 p.m.
ONT
-
SFO
Nonstop1h 44m
United Airlines
Mon 2/36:25 p.m.
SFO
-
ONT
Nonstop1h 29m
United Airlines
Deal found 26/1C$ 294
Thu 26/27:55 a.m.
ONT
-
SFO
1 stop6h 35m
Southwest
Sat 28/25:00 a.m.
SFO
-
ONT
1 stop4h 30m
Southwest
Deal found 25/1C$ 322
Wed 25/36:37 p.m.
ONT
-
SFO
Nonstop1h 33m
United Airlines
Mon 30/310:44 a.m.
SFO
-
ONT
Nonstop1h 30m
United Airlines
Deal found 26/1C$ 325
Tue 19/53:45 p.m.
ONT
-
SFO
1 stop7h 00m
Southwest
Wed 20/55:40 a.m.
SFO
-
ONT
1 stop4h 25m
Southwest
Deal found 24/1C$ 327
Wed 25/25:55 a.m.
ONT
-
SFO
2 stops6h 10m
Southwest
Wed 4/35:05 a.m.
SFO
-
ONT
1 stop4h 15m
Southwest
Deal found 26/1C$ 329
Tue 17/32:35 p.m.
ONT
-
SFO
2 stops7h 30m
Southwest
Wed 18/36:25 a.m.
SFO
-
ONT
1 stop4h 00m
Southwest
Deal found 26/1C$ 331
Wed 18/26:09 a.m.
ONT
-
SFO
Nonstop1h 33m
United Airlines
Fri 20/26:40 p.m.
SFO
-
ONT
Nonstop1h 27m
United Airlines
Deal found 26/1C$ 338

Find flight deals from Ontario to San Francisco

Discover tips and strategies to find the most affordable flight options for your journey from Ontario (ONT) to San Francisco (SFO). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated 26 January 2026.

Round-trip from

C$ 193

One-way from

C$ 131

Popular in

November

Cheapest in

May

Average price

C$ 182
Frontier
  • Frontier
  • 16/4-19/4
  • Nonstop
  • 3h 04m total
  • Ontario to San Francisco
Search Deals
Frontier
  • Frontier
  • 18/3
  • 1 total stop
  • 4h 14m total
  • Ontario to San Francisco
Search Deals
Highest demand for flights based on searches. 21% potential increase in price (C$ 75 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease (C$ 13 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in January 2026
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Ontario to San Francisco 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 629,999 searches. Data last updated 26 January 2026.
Use the filters below to find and compare flights from Ontario to San Francisco that are best for you.

Fly from

Ontario

Fly to

San Francisco

Route

Depart

Return

Price

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Mon 2/3

6:10 a.m.-7:43 a.m.

Nonstop1h 33m

San Francisco

Mon 2/3

9:30 p.m.-10:57 p.m.

Nonstop1h 27m

C$ 294

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Wed 25/3

6:37 p.m.-8:10 p.m.

Nonstop1h 33m

San Francisco

Mon 30/3

10:44 a.m.-12:14 p.m.

Nonstop1h 30m

C$ 325

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Fri 27/2

6:37 p.m.-8:10 p.m.

Nonstop1h 33m

San Francisco

Mon 2/3

9:30 p.m.-10:57 p.m.

Nonstop1h 27m

C$ 325

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Tue 19/5

3:45 p.m.-10:45 p.m.

1 stop7h 00m

San Francisco

Wed 20/5

5:40 a.m.-10:05 a.m.

1 stop4h 25m

C$ 327

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Thu 26/3

5:25 a.m.-10:00 a.m.

1 stop4h 35m

San Francisco

Mon 30/3

5:00 a.m.-12:40 p.m.

2 stops7h 40m

C$ 363

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Wed 1/4

4:25 p.m.-11:15 p.m.

2 stops6h 50m

San Francisco

Thu 2/4

5:00 a.m.-12:40 p.m.

2 stops7h 40m

C$ 368

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Tue 3/3

6:10 a.m.-7:43 a.m.

Nonstop1h 33m

San Francisco

Mon 9/3

9:30 p.m.-10:57 p.m.

Nonstop1h 27m

C$ 377

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Thu 19/2

1:50 p.m.-3:23 p.m.

Nonstop1h 33m

San Francisco

Mon 23/2

6:25 p.m.-7:54 p.m.

Nonstop1h 29m

C$ 377

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Tue 7/4

1:27 p.m.-2:56 p.m.

Nonstop1h 29m

San Francisco

Sat 18/4

10:44 a.m.-12:14 p.m.

Nonstop1h 30m

C$ 377

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Tue 17/2

1:50 p.m.-3:23 p.m.

Nonstop1h 33m

San Francisco

Wed 18/2

9:30 p.m.-10:57 p.m.

Nonstop1h 27m

C$ 377

Flights are sorted by cheapest round-trip flights first.

Deals found on 25/1

Showing 1-10 of 23 results
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Best time to book a flight from Ontario to San Francisco

Have a flexible travel schedule? Discover the best time to fly to San Francisco from Ontario 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 Ontario to San Francisco

How far ahead should I book a flight from Ontario to San Francisco?

Use this chart to determine the optimal time to book a round-trip flight from Ontario to San Francisco. Price data was last updated on 23 January 2026.

To ensure you get the cheapest price possible for a flight from Ontario to San Francisco, you should look to book at least 37 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 month to book a flight from Ontario to San Francisco?

Currently, February is the cheapest month in which you can book a flight from Ontario to San Francisco (average of C$ 26). Flying from Ontario to San Francisco in November is currently the most expensive (average of C$ 85). 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 ONT to SFO?

Find hourly flight availability from Ontario to San Francisco. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 26 January 2026.

It’s typically best to fly out from Ontario to San Francisco in the evening. Doing so could potentially save you 84% on the flight price compared to flying in the afternoon, which is usually more expensive.

Related info for your journey

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

  • How popular is this Ontario to San Francisco flight route?

    Within the past month, 15 users have taken a look at flights from Ontario to San Francisco.

  • How long is the flight from Ontario to San Francisco?

    There are many flights that can get you from Ontario to San Francisco in 1h 33m. Fly via United Airlines or Southwest to get the fastest option. The distance from Ontario to San Francisco is about 584 km. This flight may include one or multiple stops.

  • What are the most reliable airlines from Ontario to San Francisco?

    No one likes to see their flight delayed. When booking a flight from Ontario to San Francisco consider choosing United Airlines (84%), SkyWest Airlines (82%) or Frontier (71%) as they are the most reliable in getting you off to your destination on time.

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

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

  • How can I find direct flights from Ontario to San Francisco?

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

  • Can I find deals for business class flights from Ontario to San Francisco?

    Yes. Cheapflights offers flight deals from Ontario to San Francisco 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 Ontario to San Francisco?

    Currently, February is the cheapest month in which you can book a flight from Ontario to San Francisco (average of C$ 26). Flying from Ontario to San Francisco in November is currently the most expensive (average of C$ 85). 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

Travelling to a place near San Francisco?

Book flights to San Francisco if you plan to visit one of these locations
Richmond
Newark
Burlingame
South San Francisco
Scotts Valley
Novato
Santa Clara
Vallejo

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Users can book flights with no change fees policies with our dedicated filters. Book flights from Ontario to San Francisco flexibly with Cheapflights today.

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Not ready to book yet? You can track prices for flights from Ontario to San Francisco on Cheapflights with our Price Alert feature and get notified when better prices are available.

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