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

Return flights

30 Aug - 05 Sep	Icelandair	direct
23 Aug - 29 Aug	KLM
24 Aug - 02 Sep	Air France
17 Aug - 26 Aug	United
23 Aug - 29 Aug	Icelandair	direct
17 Aug - 26 Aug	Icelandair	direct
13 Aug - 11 Sep	Air France
24 Aug - 02 Sep	Icelandair	direct
02 Aug - 09 Aug	Virgin Atlantic

Also check the deals for one-way flights from Portland 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.

Book a cheap hotel in Keflavik

Cheap car rent in Keflavik

Cheapest return flights from Portland to Keflavik in August from 398€

Return flights