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

Return flights

25 Oct - 01 Nov	Avianca
28 Oct - 01 Nov	Avianca
30 Oct - 04 Nov	Avianca
28 Oct - 04 Nov	Avianca
29 Oct - 13 Nov	Southwest Airlines
27 Oct - 04 Nov	Southwest Airlines
25 Oct - 27 Oct	Avianca
27 Oct - 03 Nov	Southwest Airlines
31 Oct - 22 Nov	Southwest Airlines
26 Oct - 09 Nov	Volaris
24 Oct - 28 Oct	Southwest Airlines
27 Oct - 30 Oct	Southwest Airlines
26 Oct - 28 Oct	Volaris
24 Oct - 27 Oct	Southwest Airlines
31 Oct - 09 Nov	Southwest Airlines
24 Oct - 26 Oct	Southwest Airlines
24 Oct - 31 Oct	jetBlue

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

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 October from $361

Return flights