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

Return flights

11 Oct - 17 Oct	Delta
19 Oct - 26 Oct	Southwest Airlines
19 Oct - 02 Nov	Southwest Airlines
26 Oct - 02 Nov	Southwest Airlines
12 Oct - 26 Oct	Southwest Airlines
08 Oct - 15 Oct	Southwest Airlines
26 Oct - 09 Nov	Southwest Airlines
12 Oct - 19 Oct	Southwest Airlines
02 Oct - 06 Oct	Southwest Airlines
11 Oct - 16 Oct	United
26 Oct - 30 Oct	Southwest Airlines
16 Oct - 20 Oct	Southwest Airlines
10 Oct - 13 Oct	Southwest Airlines

Also check the deals for one-way flights from Ontario to San Juan 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 Juan in October from 288€

Return flights