Cheap flights from Ontario to San Francisco from $76

If you aren’t able to travel to San Francisco during the month of May, then flying in April is also cheap. Prices for this month can be found on momondo for an average of $128.

The cheapest day to depart from Ontario to San Francisco is on a Friday when prices can be found for as low as $201. The most expensive day to fly to San Francisco is Monday, with ticket prices averaging around $346.

Our data shows that the cheapest Ontario to San Francisco flights are usually those with departure times in the afternoon. Our users have found flights to San Francisco in the afternoon for as low as $180. Flights in the evening are often more expensive with an average ticket price of $354.

Fly from Ontario to San Francisco for the best Ontario - San Francisco flight prices

You are more likely to see cheaper flights to San Francisco from Ontario when booking weeks ahead of your departure date. In general, you can expect to find flights to San Francisco for around $165 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to San Francisco from Ontario for as low as $107 on momondo.

There are 4 cabin classes available to choose from on Ontario to San Francisco flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Southwest and United Airlines are the most popular carriers operating from Ontario to San Francisco

United Airlines, Frontier and Southwest are the top three most popular airlines that fly to San Francisco from Ontario according to our data. United Airlines is the first choice among our users, with 27% of people opting to fly with this airline when traveling to San Francisco. Keep in mind that there are 11 different airlines that fly to San Francisco on a routine basis, so you have a few additional options to choose from.

The number of flights available between Ontario and San Francisco is 6 per day as of February 2026. The most frequent departure time is 1:00PM, with 38% of daily flights leaving in the afternoon.

As of February 2026, there are 42 flights per week flying from Ontario to San Francisco. The most common day of the week flights depart is Fri, with 24% of flights taking off on this day.