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

Return flights

30 Aug - 07 Sep	Fly Play	direct
30 Aug - 02 Sep	Fly Play
30 Aug - 06 Sep	Fly Play
30 Aug - 04 Sep	Fly Play
27 Aug - 03 Sep	Ryanair
29 Aug - 02 Sep	Norwegian
30 Aug - 04 Sep	Fly Play	direct
29 Aug - 01 Sep	Norwegian
26 Aug - 04 Sep	Fly Play	direct
28 Aug - 01 Sep	TAP
22 Aug - 28 Aug	Ryanair
23 Aug - 28 Aug	SWISS
23 Aug - 26 Aug	SWISS
26 Aug - 30 Aug	Fly Play	direct
21 Aug - 28 Aug	SWISS
23 Aug - 30 Aug	SWISS
21 Aug - 24 Aug	SWISS
22 Aug - 25 Aug	Ryanair
19 Aug - 26 Aug	TAP
19 Aug - 23 Aug	Ryanair

Also check the deals for one-way flights from Porto 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 Porto to Keflavik in August from $259

Return flights