Great-circle route SEA ↔ KEF. Faint dots are other airports, for geographic context. Download this map — free to reuse with a link back to this page.
Frequencies below are per direction, from our most recent schedule sample.
| Direction | Frequency | Days | Airlines |
|---|---|---|---|
| SEA → KEF Seattle to Reykjavik |
27/wk | Daily | Alaska Airlines, Icelandair |
| KEF → SEA Reykjavik to Seattle |
— | — | Alaska Airlines, Icelandair |
Where a direction shows “—” we track it as an operating nonstop but hold no schedule sample for it — we would rather show nothing than guess.
In 2025, airlines reported 205,225 passengers on 1,347 flights between SEA and KEF — about 563 a day — filling 81% of the 252,118 seats flown. Icelandair carried the most passengers (100%).
Source: US DOT T-100 segment reports — actual airline-reported traffic, scheduled service only, both directions combined. Cargo and charter flights excluded.
2 airlines fly the SEA–KEF nonstop, including Alaska Airlines, Icelandair.
Recent scheduled departures on this route have used the Boeing 737.
Aircraft assignments change by season and by time of day.
On a long east–west route like this one the two directions do not take the same time. Aircraft flying eastbound ride the mid-latitude jet stream and typically arrive earlier than the westbound leg, which flies into it. The difference is commonly 30 to 90 minutes on transatlantic and transpacific flights, and it varies by season. The estimate above does not model wind — treat it as a midpoint and check the airline's own timetable for the block time on your date.
The distance between Seattle Tacoma International Airport and Keflavik International Airport is 3,611 miles, or 5,811 kilometres.
| Great-circle distance | 3,611 mi |
| Kilometres | 5,811 km |
| Nautical miles | 3,138 nmi |
Measured airport to airport. The actual track is longer — aircraft follow airways, avoid restricted airspace and route around weather.
Yes. 2 airlines fly the route nonstop, with about 27 departures a week across both directions. The route is in our live nonstop dataset, last seeded 2026-07-07.
About 7h 30m in the air. That is a great-circle estimate from the 3,611-mile distance, not a scheduled block time — an airline's published time will differ by roughly 15 to 45 minutes depending on routing, winds and taxi.
Alaska Airlines, Icelandair.
In 2025, airlines reported 205,225 passengers on 1,347 scheduled flights between SEA and KEF — about 563 a day — filling 81% of the seats flown. Source: US DOT T-100 segment reports, both directions combined.
Recent scheduled departures have used the Boeing 737. Assignments change by season and by time of day.
