AirHint found the following cheapest return flights from Castellón (CDT) to Porto (OPO) in September 2025 (see full year).

Return flights

23 Sep - 30 Sep	Ryanair	direct
13 Sep - 16 Sep	Ryanair	direct
13 Sep - 23 Sep	Ryanair	direct
13 Sep - 30 Sep	Ryanair	direct
20 Sep - 23 Sep	Ryanair	direct
20 Sep - 30 Sep	Ryanair	direct
13 Sep - 20 Sep	Ryanair	direct
23 Sep - 27 Sep	Ryanair	direct
13 Sep - 27 Sep	Ryanair	direct
20 Sep - 27 Sep	Ryanair	direct
27 Sep - 04 Oct	Ryanair
29 Sep - 06 Oct	Iberia
01 Sep - 01 Oct	Ryanair

Also check the deals for one-way flights from Castellón to Porto in September.

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 Castellón to Porto in September from 36€

Return flights