AirHint found the following cheapest return flights from Ontario (ONT) to San Juan (SJU) in May 2026 (see full year).

Return flights

07 May - 14 May	United
04 May - 11 May	United
09 May - 17 May	Southwest Airlines
01 May - 08 May	Southwest Airlines
01 May - 09 May	Southwest Airlines
18 May - 21 May	Southwest Airlines
14 May - 18 May	Southwest Airlines
28 May - 03 Jun	Southwest Airlines
06 May - 12 May	Southwest Airlines
06 May - 11 May	Southwest Airlines
20 May - 25 May	Southwest Airlines

Also check the deals for one-way flights from Ontario to San Juan in May.

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 May from $310

Return flights