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

Return flights

30 Oct - 22 Nov	Air France
30 Oct - 26 Nov	Air France
21 Oct - 15 Nov	WestJet
22 Oct - 15 Nov	KLM
25 Oct - 05 Nov	KLM
17 Oct - 08 Nov	Air France
22 Oct - 29 Oct	KLM
26 Oct - 29 Oct	KLM
24 Oct - 15 Nov	Air France
18 Oct - 22 Oct	KLM
23 Oct - 30 Oct	Air France
20 Oct - 27 Oct	Qatar Airways
24 Oct - 15 Nov	Turkish Airlines	direct
30 Oct - 26 Nov	Turkish Airlines	direct
25 Oct - 12 Nov	Delta
20 Oct - 27 Oct	Turkish Airlines	direct
18 Oct - 22 Oct	Turkish Airlines	direct
18 Oct - 25 Oct	Lufthansa
25 Oct - 31 Oct	WestJet
18 Oct - 25 Oct	Turkish Airlines	direct

Also check the deals for one-way flights from Seattle to Istanbul 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 Istanbul in October from 632€

Return flights