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

Return flights

24 Sep - 22 Oct	Air Canada
22 Sep - 29 Sep	Iberia
09 Sep - 16 Sep	Iberia
03 Sep - 10 Sep	Iberia	direct
17 Sep - 24 Sep	United
18 Sep - 22 Sep	American Airlines
27 Sep - 04 Oct	Iberia
12 Sep - 19 Sep	Iberia
06 Sep - 13 Sep	Iberia	direct
06 Sep - 13 Sep	United
11 Sep - 15 Sep	American Airlines	direct
24 Sep - 22 Oct	Finnair	direct

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 $523

Return flights