Cheapest return flights from Seattle to London in December from $507

AirHint found the following cheapest return flights from Seattle (SEA) to London (LHR) in December 2025 (see full year).

Return flights

03 Dec - 16 Dec Air Canada
03 Dec - 16 Dec Air France direct
02 Dec - 16 Dec Delta direct
04 Dec - 11 Dec Icelandair
30 Dec - 19 Jan Icelandair
11 Dec - 16 Dec Air Canada
11 Dec - 16 Dec American Airlines direct
04 Dec - 11 Dec British Airways direct
30 Dec - 19 Jan British Airways direct
16 Dec - 25 Dec Delta
05 Dec - 13 Dec Icelandair
11 Dec - 20 Dec Icelandair
15 Dec - 25 Jan KLM
13 Dec - 24 Jan KLM
15 Dec - 25 Jan British Airways direct
13 Dec - 24 Jan British Airways direct
13 Dec - 06 Jan Icelandair
11 Dec - 04 Jan Icelandair
13 Dec - 06 Jan Delta direct
14 Dec - 02 Jan Virgin Atlantic

Also check the deals for one-way flights from Seattle to London in December.

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.

Book a cheap hotel in London

Cheap car rent in London

Feel free to contact us with any feedback or request another flight research.