AirHint found the following cheapest return flights from Keflavik (KEF) to Lisbon (LIS) in September 2025 (see full year).
Return flights
| 05 Sep - 08 Sep | Transavia France | ||
| 27 Sep - 07 Oct | Scandinavian Airlines | ||
| 26 Sep - 06 Oct | Fly Play | ||
| 05 Sep - 08 Sep | Fly Play | direct | |
| 26 Sep - 06 Oct | Fly Play | direct |
Also check the deals for one-way flights from Keflavik to Lisbon 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.
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