AirHint found the following cheapest return flights from San Francisco (SFO) to San Juan (SJU) in August 2025 (see full year).

Return flights

25 Aug - 30 Aug	United
23 Aug - 29 Aug	United
31 Aug - 09 Sep	United
19 Aug - 23 Aug	United
12 Aug - 19 Aug	United
21 Aug - 29 Aug	Southwest Airlines
10 Aug - 15 Aug	United
17 Aug - 23 Aug	United
09 Aug - 15 Aug	Frontier Airlines
13 Aug - 19 Aug	United
10 Aug - 14 Aug	United
22 Aug - 05 Sep	Frontier Airlines
28 Aug - 05 Sep	Southwest Airlines
29 Aug - 03 Sep	United
27 Aug - 01 Sep	Alaska Airlines
29 Aug - 01 Sep	Frontier Airlines
28 Aug - 02 Sep	Alaska Airlines
28 Aug - 01 Sep	Alaska Airlines

Also check the deals for one-way flights from San Francisco to San Juan in August.

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 San Francisco to San Juan in August from 316€

Return flights