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

Return flights

16 Aug - 03 Sep	Alaska Airlines
05 Aug - 29 Aug	Alaska Airlines
19 Aug - 02 Sep	Icelandair
27 Aug - 19 Sep	Icelandair
27 Aug - 04 Sep	jetBlue
27 Aug - 07 Sep	jetBlue
09 Aug - 23 Aug	jetBlue
01 Aug - 23 Aug	jetBlue
11 Aug - 20 Aug	jetBlue
13 Aug - 05 Sep	Turkish Airlines
14 Aug - 05 Sep	Icelandair
07 Aug - 24 Aug	Alaska Airlines
07 Aug - 21 Aug	Alaska Airlines

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

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 London in August from $811

Return flights