Cheapest return flights from Seattle to London in April from $542

AirHint found the following cheapest return flights from Seattle (SEA) to London (LHR) in April 2026 (see full year).

Return flights

15 Apr - 22 Apr Icelandair
22 Apr - 27 Apr Icelandair
13 Apr - 20 Apr Icelandair
23 Apr - 28 Apr Icelandair
20 Apr - 29 Apr Icelandair
15 Apr - 19 Apr Icelandair
29 Apr - 06 May Icelandair
06 Apr - 07 May Icelandair
30 Apr - 19 May Icelandair
22 Apr - 29 Apr Icelandair
25 Apr - 09 May Icelandair
06 Apr - 13 Apr Icelandair
21 Apr - 05 May Icelandair
23 Apr - 06 May Icelandair
25 Apr - 02 May Icelandair
01 Apr - 10 Apr Aer Lingus
08 Apr - 14 Apr KLM
21 Apr - 05 May Virgin Atlantic direct
29 Apr - 06 May American Airlines direct
27 Apr - 03 May Icelandair

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

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