Cheapest return flights from Lisbon to Keflavik in September from $181

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

Return flights

19 Sep - 29 Sep Fly Play direct
17 Sep - 28 Sep Ryanair
12 Sep - 15 Sep Fly Play direct
05 Sep - 15 Sep Fly Play direct
25 Sep - 28 Sep Ryanair
18 Sep - 28 Sep Ryanair
24 Sep - 29 Sep Ryanair
09 Sep - 17 Sep easyJet
16 Sep - 23 Sep Vueling Airlines
18 Sep - 22 Sep Ryanair
24 Sep - 16 Oct Ryanair

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

Skyscanner

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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