AirHint found the following cheapest return flights from Seattle (SEA) to Keflavik (KEF) in March 2026 (see full year).

Return flights

05 Mar - 12 Mar	Lufthansa
21 Mar - 05 Apr	Lufthansa
06 Mar - 13 Mar	Icelandair	direct
07 Mar - 14 Mar	British Airways
07 Mar - 14 Mar	Icelandair	direct
05 Mar - 12 Mar	Icelandair	direct
03 Mar - 10 Mar	Icelandair	direct
21 Mar - 05 Apr	Icelandair	direct

Also check the deals for one-way flights from Seattle to Keflavik in March.

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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Cheapest return flights from Seattle to Keflavik in March from 441€

Return flights