Cheapest one-way flights from Seattle to Barcelona in September from 239€

AirHint found the following cheapest one-way flights from Seattle (SEA) to Barcelona (BCN) in September 2025 (see full year).

One-Way flights

27 Sep Hawaiian Airlines
28 Sep Alaska Airlines
23 Sep Hawaiian Airlines
20 Sep Hawaiian Airlines
26 Sep Frontier Airlines
25 Sep Frontier Airlines
21 Sep Frontier Airlines
14 Sep Alaska Airlines
24 Sep Alaska Airlines
15 Sep Frontier Airlines

Also check the deals for return flights from Seattle to Barcelona in September.

Skyscanner

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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