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

Return flights

16 Aug - 23 Aug	Frontier Airlines
17 Aug - 24 Aug	Frontier Airlines
18 Aug - 22 Aug	Alaska Airlines
06 Aug - 19 Aug	Hawaiian Airlines
27 Aug - 03 Sep	Alaska Airlines
04 Aug - 20 Aug	Air Canada
13 Aug - 21 Aug	Air Canada
07 Aug - 14 Aug	Hawaiian Airlines
18 Aug - 25 Aug	United
22 Aug - 29 Aug	United
24 Aug - 31 Aug	United
26 Aug - 02 Sep	United
28 Aug - 04 Sep	United
31 Aug - 07 Sep	United

Also check the deals for one-way flights from San Francisco to Keflavik 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 Keflavik in August from 433€

Return flights