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

Return flights

24 Jul - 02 Aug	Icelandair
30 Jul - 05 Aug	Icelandair
31 Jul - 03 Aug	Icelandair
29 Jul - 05 Aug	Icelandair
07 Jul - 18 Jul	SWISS
11 Jul - 18 Jul	Air Canada
14 Jul - 21 Jul	Air Canada
10 Jul - 17 Jul	Air Canada
18 Jul - 21 Jul	Lufthansa
09 Jul - 16 Jul	Air France
22 Jul - 28 Jul	Icelandair
30 Jul - 02 Aug	Scandinavian Airlines
25 Jul - 27 Jul	Lufthansa
22 Jul - 29 Jul	Icelandair
20 Jul - 31 Jul	Icelandair
25 Jul - 02 Aug	Icelandair
16 Jul - 02 Aug	Lufthansa
17 Jul - 03 Aug	Air Canada
21 Jul - 05 Aug	Aer Lingus
26 Jul - 14 Aug	Hawaiian Airlines

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

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 July from $539

Return flights