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

Return flights

24 Oct - 31 Oct	Volaris
16 Oct - 20 Oct	Frontier Airlines
05 Oct - 12 Oct	Frontier Airlines
04 Oct - 26 Oct	Frontier Airlines
07 Oct - 12 Oct	Frontier Airlines
31 Oct - 09 Nov	Frontier Airlines
31 Oct - 08 Nov	Frontier Airlines
30 Oct - 03 Nov	Frontier Airlines
30 Oct - 09 Nov	Aeromexico
30 Oct - 02 Nov	Volaris
29 Oct - 04 Nov	Hawaiian Airlines
24 Oct - 03 Nov	Frontier Airlines
30 Oct - 09 Nov	Aeromexico	direct

Also check the deals for one-way flights from Seattle to Mexico City 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 Mexico City in October from 276€

Return flights