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

Return flights

29 Oct - 05 Nov	Lufthansa
01 Oct - 09 Oct	Aer Lingus
29 Oct - 04 Nov	Lufthansa
20 Oct - 29 Oct	Aer Lingus
22 Oct - 29 Oct	Aer Lingus
07 Oct - 21 Oct	Aer Lingus
01 Oct - 09 Oct	Virgin Atlantic	direct
29 Oct - 04 Nov	Virgin Atlantic	direct
28 Oct - 04 Nov	Virgin Atlantic
08 Oct - 24 Oct	Air Canada
29 Oct - 03 Nov	Air Canada
22 Oct - 27 Oct	Air Canada
08 Oct - 15 Oct	Air France
28 Oct - 03 Nov	Virgin Atlantic
01 Oct - 21 Oct	Delta
08 Oct - 21 Oct	Delta
08 Oct - 27 Nov	Delta
30 Oct - 05 Nov	Lufthansa
29 Oct - 05 Nov	Virgin Atlantic	direct
08 Oct - 27 Nov	British Airways	direct

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

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 October from 395€

Return flights