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

Return flights

17 Sep - 24 Sep	jetBlue
23 Sep - 30 Sep	United
29 Sep - 06 Oct	Iberia
26 Sep - 03 Oct	Iberia
19 Sep - 24 Sep	United
01 Sep - 09 Sep	Air Canada
08 Sep - 23 Sep	British Airways	direct
02 Sep - 09 Sep	Iberia
20 Sep - 27 Sep	United
18 Sep - 04 Oct	United
08 Sep - 15 Sep	Iberia	direct
14 Sep - 21 Sep	Iberia	direct
10 Sep - 21 Sep	Air Canada
28 Sep - 04 Oct	Finnair

Also check the deals for one-way flights from Philadelphia to Madrid 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 Madrid in September from 440€

Return flights