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

Return flights

06 Sep - 12 Sep	Spirit Airlines
09 Sep - 16 Sep	United
03 Sep - 10 Sep	United
24 Sep - 01 Oct	United
09 Sep - 23 Sep	Frontier Airlines
30 Sep - 07 Oct	United
15 Sep - 22 Sep	Lufthansa
12 Sep - 27 Sep	Frontier Airlines
18 Sep - 25 Sep	United
19 Sep - 03 Oct	Spirit Airlines
23 Sep - 06 Oct	Lufthansa
04 Sep - 08 Sep	Lufthansa
12 Sep - 19 Sep	United
11 Sep - 14 Sep	United
27 Sep - 04 Oct	United

Also check the deals for one-way flights from Philadelphia 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 Philadelphia to Athens in September from 575€

Return flights