AirHint found the following cheapest return flights from Seattle (SEA) to San Jose (SJO) in August 2025 (see full year).

Return flights

18 Aug - 03 Sep	Hawaiian Airlines
13 Aug - 23 Aug	Alaska Airlines
01 Aug - 30 Sep	United
01 Aug - 12 Aug	Frontier Airlines
03 Aug - 07 Aug	United
04 Aug - 09 Aug	United
05 Aug - 11 Aug	Spirit Airlines

Also check the deals for one-way flights from Seattle to San Jose 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 Seattle to San Jose in August from 415€

Return flights