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

Return flights

30 Dec - 07 Jan	Southwest Airlines
25 Dec - 09 Jan	Southwest Airlines
15 Dec - 30 Dec	Southwest Airlines
25 Dec - 30 Dec	Avianca
24 Dec - 29 Dec	Southwest Airlines
22 Dec - 30 Dec	Southwest Airlines
24 Dec - 03 Jan	Southwest Airlines
27 Dec - 03 Jan	Southwest Airlines
19 Dec - 04 Jan	Southwest Airlines
26 Dec - 04 Jan	Southwest Airlines
19 Dec - 02 Jan	Southwest Airlines
21 Dec - 03 Jan	Southwest Airlines

Also check the deals for one-way flights from Ontario to San Jose 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.

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Cheapest return flights from Ontario to San Jose in December from 733€

Return flights