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

Return flights

24 Aug - 09 Sep	Air Canada
14 Aug - 27 Aug	Air Canada
18 Aug - 27 Aug	TAP	direct
18 Aug - 01 Sep	TAP
11 Aug - 21 Aug	TAP	direct
25 Aug - 08 Sep	Brussels Airlines
13 Aug - 21 Aug	TAP	direct
07 Aug - 21 Aug	Air Canada
20 Aug - 27 Aug	United
20 Aug - 28 Aug	United
16 Aug - 28 Aug	Air Canada
17 Aug - 24 Aug	LEVEL
25 Aug - 06 Sep	Brussels Airlines
23 Aug - 09 Sep	LEVEL
04 Aug - 18 Aug	British Airways
21 Aug - 04 Sep	Air Canada
24 Aug - 04 Sep	Brussels Airlines
23 Aug - 06 Sep	Air Canada
25 Aug - 04 Sep	Air Canada
25 Aug - 09 Sep	Air Canada

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 $570

Return flights