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

Return flights

16 Oct - 20 Oct	KLM
08 Oct - 11 Oct	easyJet
09 Oct - 12 Oct	KLM
03 Oct - 06 Oct	Fly Play	direct
31 Oct - 03 Nov	Fly Play	direct
30 Oct - 03 Nov	easyJet
10 Oct - 13 Oct	KLM
30 Oct - 02 Nov	easyJet
02 Oct - 06 Oct	easyJet
10 Oct - 13 Oct	Fly Play	direct
01 Oct - 05 Oct	easyJet
09 Oct - 12 Oct	Icelandair	direct
30 Oct - 02 Nov	Icelandair	direct

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

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 Lisbon

Cheap car rent in Lisbon

Cheapest return flights from Keflavik to Lisbon in October from 274€

Return flights