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

Return flights

13 Aug - 20 Aug	Air Canada
20 Aug - 15 Sep	SWISS
14 Aug - 20 Sep	Iberia For Level
20 Aug - 28 Aug	Air Canada
20 Aug - 27 Aug	United
20 Aug - 01 Sep	SWISS
04 Aug - 25 Aug	Lufthansa
11 Aug - 21 Aug	SWISS
14 Aug - 27 Aug	Air Canada
13 Aug - 21 Aug	Air France
04 Aug - 18 Aug	Air France
18 Aug - 30 Aug	United
15 Aug - 29 Aug	United
21 Aug - 01 Sep	Iberia
25 Aug - 01 Sep	Lufthansa
31 Aug - 13 Sep	Air Canada
30 Aug - 04 Sep	Frontier Airlines
28 Aug - 08 Sep	Frontier Airlines
30 Aug - 06 Sep	Hawaiian Airlines
26 Aug - 02 Sep	United

Also check the deals for one-way flights from San Francisco to Lisbon 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 Lisbon in August from 533€

Return flights