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

Return flights

17 Aug - 26 Aug	United
14 Aug - 21 Aug	Air Canada
18 Aug - 25 Aug	United
20 Aug - 28 Aug	Air Canada
26 Aug - 18 Sep	Air Canada
15 Aug - 20 Aug	Air Canada
16 Aug - 23 Aug	Air Canada
11 Aug - 20 Aug	United
22 Aug - 29 Aug	Air Canada
21 Aug - 29 Aug	Air Canada
21 Aug - 26 Aug	Air Canada
29 Aug - 05 Sep	United
28 Aug - 03 Sep	Air Canada
29 Aug - 01 Sep	Air Canada
27 Aug - 02 Sep	Scandinavian Airlines
18 Aug - 17 Sep	Icelandair
30 Aug - 04 Sep	Icelandair
29 Aug - 07 Sep	Icelandair
31 Aug - 06 Sep	Icelandair
29 Aug - 06 Sep	Icelandair

Also check the deals for one-way flights from Washington 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 Washington to Keflavik in August from $493

Return flights