AirHint found the following cheapest return flights from San Francisco (SFO) to Ontario (ONT) in December 2025 (see full year).

Return flights

03 Dec - 10 Dec	Southwest Airlines
22 Dec - 31 Dec	Southwest Airlines
23 Dec - 06 Jan	Southwest Airlines
22 Dec - 29 Dec	Southwest Airlines
30 Dec - 02 Jan	Southwest Airlines
23 Dec - 27 Dec	Southwest Airlines
29 Dec - 01 Jan	Southwest Airlines
20 Dec - 27 Dec	Southwest Airlines

Also check the deals for one-way flights from San Francisco to Ontario in December.

The deals are updated regularly. The prices may go up as tickets are purchased by other travellers. Only the cheapest flights are offered. Select a price to book and secure these cheap prices.

Book a cheap hotel in Ontario

Cheap car rent in Ontario

Cheapest return flights from San Francisco to Ontario in December from 128€

Return flights