5 hr 18 min is the shortest flight time from San Francisco to Cancún.

The cheapest days to fly are usually in January. Typical prices range from $225 to $335.

The best round-trip deal recently found on Google Flights from San Francisco to Cancún was with Aeromexico from $316. The best one-way deal was with Aeromexico from $140.

There are direct flights from San Francisco to Cancún on a daily basis.

United and Alaska fly direct from San Francisco to Cancún.

The cheapest round-trip flight from San Francisco to Cancún starts at $316 from Thu, Aug 15 to Thu, Aug 22. The cheapest one-way flight starts at $140 and departs on Wed, Aug 21.

Peak season is winter (Dec–Apr), becoming busiest during U.S. university students’ spring break (Mar–Apr, dates vary). Summer (Jun–Aug) is very hot and humid. Fall (Sep–Nov) is warm, with a chance of hurricanes. Visits from mid-Jun–late Aug offer the opportunity to snorkel with giant whale sharks off the coast of Isla Holbox, while sea turtle nesting season is Jun–Aug. Key events and holidays include Cinco de Mayo (May 5) and the Cancún Jazz Festival (Sep).

It's easy to use Google Flights to find the cheapest days to fly from San Francisco to Cancún.
Just click the Departure label near the top of the page to open the calendar. Choose a start date and a return date to see how the round-trip fare changes on those specific days.
Adjust the trip type to see one-way fares. The cheapest available flights are highlighted and easy to spot. Once you settle on dates, click the Search button to see flight options and book the deal.

You can also turn on price tracking to get alerts if the price changes for a route or flight.