49 € Ontario International to San Francisco International Cheap Flights

Compare Ontario International to San Francisco International flight deals

Find the cheapest month or even day of the year to fly to San Francisco International

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Flight deals from Ontario International to San Francisco International

Looking for a cheap last-minute deal or the best return flight from Ontario International to San Francisco International? Find the lowest prices on one-way and return tickets right here.

San Francisco.49 € per passenger.Departing Wed, 30 Jul, returning Fri, 1 Aug.Return flight with United.Outbound direct flight with United departs from Ontario International on Wed, 30 Jul, arriving in San Francisco International.Inbound direct flight with United departs from San Francisco International on Fri, 1 Aug, arriving in Ontario International.Price includes taxes and charges.From 49 €, select.

San Francisco.49 € per passenger.Departing Sat, 2 Aug, returning Mon, 4 Aug.Return flight with United.Outbound direct flight with United departs from Ontario International on Sat, 2 Aug, arriving in San Francisco International.Inbound direct flight with United departs from San Francisco International on Mon, 4 Aug, arriving in Ontario International.Price includes taxes and charges.From 49 €, select.

San Francisco.54 € per passenger.Departing Fri, 25 Jul, returning Mon, 28 Jul.Return flight with Frontier Airlines.Outbound direct flight with Frontier Airlines departs from Ontario International on Fri, 25 Jul, arriving in San Francisco International.Inbound direct flight with Frontier Airlines departs from San Francisco International on Mon, 28 Jul, arriving in Ontario International.Price includes taxes and charges.From 54 €, select.

San Francisco.72 € per passenger.Departing Thu, 11 Sep, returning Sun, 14 Sep.Return flight with Frontier Airlines.Outbound direct flight with Frontier Airlines departs from Ontario International on Thu, 11 Sep, arriving in San Francisco International.Inbound direct flight with Frontier Airlines departs from San Francisco International on Sun, 14 Sep, arriving in Ontario International.Price includes taxes and charges.From 72 €, select.

San Francisco.75 € per passenger.Departing Fri, 29 Aug, returning Mon, 1 Sep.Return flight with Frontier Airlines.Outbound direct flight with Frontier Airlines departs from Ontario International on Fri, 29 Aug, arriving in San Francisco International.Inbound direct flight with Frontier Airlines departs from San Francisco International on Mon, 1 Sep, arriving in Ontario International.Price includes taxes and charges.From 75 €, select.

San Francisco.75 € per passenger.Departing Fri, 17 Oct, returning Fri, 24 Oct.Return flight with Frontier Airlines.Outbound direct flight with Frontier Airlines departs from Ontario International on Fri, 17 Oct, arriving in San Francisco International.Inbound direct flight with Frontier Airlines departs from San Francisco International on Fri, 24 Oct, arriving in Ontario International.Price includes taxes and charges.From 75 €, select.

San Francisco.117 € per passenger.Departing Tue, 9 Dec, returning Thu, 18 Dec.Return flight with United.Outbound direct flight with United departs from Ontario International on Tue, 9 Dec, arriving in San Francisco International.Inbound direct flight with United departs from San Francisco International on Thu, 18 Dec, arriving in Ontario International.Price includes taxes and charges.From 117 €, select.

San Francisco.121 € per passenger.Departing Mon, 30 Jun, returning Fri, 4 Jul.Return flight with Frontier Airlines.Outbound direct flight with Frontier Airlines departs from Ontario International on Mon, 30 Jun, arriving in San Francisco International.Inbound direct flight with Frontier Airlines departs from San Francisco International on Fri, 4 Jul, arriving in Ontario International.Price includes taxes and charges.From 121 €, select.

Find the cheapest month to fly from Ontario International to San Francisco International

We’re always keeping an eye on fares, so you can find the best one in seconds. It looks like Ontario International to San Francisco International flights are currently cheapest in August.

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Direct flights from Ontario International to San Francisco International

Ontario International to San Francisco International: Alternative routes

Compare routes from Ontario International to San Francisco below. You may find an airport to fly into that's cheaper, faster, or easier than San Francisco International.

Ontario to San Francisco: Flight information

The things to know before you go.

Cheapest flight found	49 €
Cheapest month to fly	August
Average flight time	1 hr, 30 mins
Most popular airline	United
Average flights per week	79

Finding cheap flights from Ontario International to San Francisco International: Frequently asked questions

How much are return flights from Ontario International to San Francisco International?

The best price we found for a return flight from Ontario International to San Francisco International is 49 €. This is an estimate based on information collected from different airlines and travel providers over the last 4 days and is subject to change and availability.

How long does it take to fly from Ontario International to San Francisco International?

1 hour and 30 minutes is the average flight time from Ontario International to San Francisco International.

Which airlines fly direct from Ontario International to San Francisco International?

United, Air Canada and SkyWest Airlines fly direct from Ontario International to San Francisco International.

How many flights are there a week from Ontario International to San Francisco International?

As of July 2025, there are 79 flights per week flying from Ontario International to San Francisco International.

When is the cheapest time to fly from Ontario International to San Francisco International?

The cheapest month to fly from Ontario International to San Francisco International is usually August.

Which upcoming date is cheapest to fly from Ontario International Airport to San Francisco International Airport on?

After crunching the numbers on our flight calendar, we found that it's currently cheapest to fly from Ontario International Airport to San Francisco International Airport on Saturday, 2 August 2025.

Can I get a direct flight from Ontario International Airport to San Francisco International Airport?

Yes – the average flight time is 1 hour and 30 minutes.

How can I find the best flight deal to San Francisco International?

We show every price from over 1,200 airlines and travel agents, comparing them all so you don’t have to. If you know you want to fly to San Francisco International but you’re not ready to book, set up a Price Alert. We’ll track prices for you, and let you know when they rise or fall.

When is the best time to book flights to San Francisco?

We crunched all the numbers in our flight calendar and it looks like the cheapest time to book a flight to San Francisco is around 40 days in advance, so don’t leave your flight to the last minute.

Which is the cheapest airline to fly from Ontario International Airport to San Francisco International with?

Currently, United offers the cheapest flight tickets to San Francisco International.

Travelling from Ontario International Airport (ONT) to San Francisco International Airport (SFO): what you need to know

The average length of a direct flight from Ontario International Airport to San Francisco International Airport is 1 hour 25 minutes.
San Francisco's timezone is UTC-7, which is the same as Ontario.
Take your pick of 89 weekly Ontario International Airport to San Francisco International Airport flights. The 06:00 departure with United Airlines is the earliest available. United Airlines operates the last service of the day at 20:18.
Arrive at the airport on time so you don't miss your ONT to SFO flight. Be there at least two hours ahead for international flights and an hour early for domestic departures to avoid the stress of rushing.
Flying during a peak time like August? Public holidays and other high seasons can result in longer lines at security. Play it safe and get there up to four hours ahead of international flights and two hours before a domestic departure.
Frontier Airlines has direct flights from Ontario International Airport to San Francisco International Airport. Book with this popular airline, then get ready to discover the sights in San Francisco — and maybe even more of United States if you have time.
Frontier Airlines is the airline with the highest passenger demand for this route.
United Airlines is the most punctual carrier that operates ONT to SFO flights, with 74.58% of its services reaching their destination on time.
We make it easy to book a flight with a stopover. To see all your options for tickets from Ontario International Airport to San Francisco International Airport, deselect 'Direct flights only.' Then, choose a flight with a stop long enough to tour the city of your choice. Some great stopovers between ONT and SFO include:
- Sacramento International Airport
- Harry Reid Airport (formerly McCarran Airport)
- Phoenix Sky Harbour International Airport

How to find the cheapest flights from Ontario International Airport (ONT) to San Francisco International Airport (SFO)

The lowest price we've found for a one-way Ontario International Airport to San Francisco International Airport flight is 16 €. A round-trip plane ticket is currently 49 €. Depending on the availability and when you book, these fares may change.
Score cheap tickets from ONT to SFO by booking at least five months ahead. According to our research, that's the sweet spot for finding the biggest deals.
April is the cheapest month for flights from Ontario International Airport to San Francisco International Airport. If you want to travel during a different time of year, the 'Whole month' tool will give you the lowest airfares for every month.
You don't need to check every day to see if fares have gone down when you set up a Price Alert. We'll let you know the moment there's a better deal on cheap flights from ONT to SFO.
Lock in the right flight for you with the help of the filters. To see the 'Cheapest,' 'Best' or 'Fastest' flights from Ontario International Airport to San Francisco International Airport, use the 'Sort by' function. You can also filter by airline, departure and arrival times, and number of stops.

Handy information about Ontario International Airport (ONT)

ONT is located at 2900 E. Airport Drive.
Ontario International Airport maintains a solid on-time record, so you're unlikely to face delays. Departures from ONT arrive on schedule 83.6% of the time.
Ontario International Airport is about 6 kilometres from central Ontario. If you're driving, ride-sharing or catching a cab from the centre, it'll take 10 minutes or so to get there, depending on the traffic.
Expect a trip time of about 1 hour 30 minutes when using public transport.
Get your travels off to a leisurely start by staying near ONT. Whether you're boarding an early flight from Ontario International Airport to San Francisco International Airport or just don't like being rushed, these hotels are ideal:

Arriving at San Francisco International Airport (SFO)

The last thing you want is a lengthy journey to your hotel if you're getting in late on an Ontario International Airport to San Francisco International Airport flight. Stay at one of these accommodation options near SFO instead:
Travel at your own pace with a San Francisco International Airport rental car. Pick up your wheels from Dollar, Thrifty or Hertz and chase adventure across San Francisco and beyond.
Reserving your vehicle from San Francisco International Airport about one week ahead can help you get the best possible rate.

Getting from San Francisco International Airport (SFO) to central San Francisco

From San Francisco International Airport, San Francisco is approximately 21 kilometres away. It takes around 20 minutes to reach the centre by car.
When travelling by public transport, expect a journey time of about 45 minutes.

When to fly to San Francisco International Airport (SFO)

The quietest month for a flight from Ontario International Airport to San Francisco International Airport is February, while August is the busiest. Pick the best time to visit San Francisco based on whether you prefer a faster pace or a more relaxed vibe.
The warmest month in San Francisco is September, with the temperature ranging between 12ºC (54ºF) and 22ºC (72ºF). Book your flights from Ontario International Airport to San Francisco International Airport in this month if you like this kind of weather.
For cooler conditions, look for a cheap ticket from ONT to SFO in January. Temperatures average between 6ºC (43ºF) and 16ºC (61ºF) then.

Explore more of United States

San Francisco is easy to fall in love with, but there are so many other parts of United States waiting to be discovered. Around 64 kilometres south-east of San Francisco, a visit to San Jose will keep you on the move. Check out popular attractions like Winchester Mystery House, Rosicrucian Egyptian Museum and San Jose Museum of Art.
Fresno is another favourite destination in United States and is around 257 kilometres south-east of San Francisco. No trip is complete without dropping by Forestiere Underground Gardens, Fresno Chaffee Zoo and Shinzen Japanese Garden.