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

Return flights

24 Sep - 29 Sep	easyJet
30 Sep - 08 Oct	easyJet
23 Sep - 29 Sep	easyJet
21 Sep - 29 Sep	easyJet
16 Sep - 22 Oct	easyJet
29 Sep - 04 Oct	easyJet
25 Sep - 29 Sep	easyJet
25 Sep - 30 Sep	Ryanair
23 Sep - 30 Sep	Ryanair
28 Sep - 04 Oct	easyJet
24 Sep - 01 Oct	easyJet
11 Sep - 16 Sep	Wizz Air Malta
16 Sep - 30 Sep	Vueling Airlines
23 Sep - 07 Oct	easyJet
22 Sep - 29 Sep	easyJet
16 Sep - 01 Oct	Vueling Airlines
27 Sep - 30 Sep	Ryanair
30 Sep - 02 Oct	easyJet
21 Sep - 07 Oct	easyJet
29 Sep - 09 Oct	easyJet

Also check the deals for one-way flights from Porto to Athens 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 Porto to Athens in September from $173

Return flights