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

Return flights

11 Sep - 18 Sep	KLM
11 Sep - 21 Sep	Fly Play	direct
28 Sep - 02 Oct	Fly Play	direct
18 Sep - 02 Oct	Fly Play	direct
25 Sep - 02 Oct	Fly Play	direct
19 Sep - 23 Sep	Ryanair
18 Sep - 25 Sep	Fly Play	direct
18 Sep - 21 Sep	Fly Play	direct
29 Sep - 05 Oct	Ryanair
12 Sep - 18 Sep	Ryanair
04 Sep - 07 Sep	KLM
23 Sep - 30 Sep	Ryanair
17 Sep - 20 Sep	Ryanair
10 Sep - 20 Sep	Ryanair
21 Sep - 05 Oct	Ryanair

Also check the deals for one-way flights from Porto to Keflavik in September.

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 Porto to Keflavik in September from 237€

Return flights