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

Return flights

10 Sep - 16 Sep	United
10 Sep - 17 Sep	United
02 Sep - 11 Sep	United
02 Sep - 16 Sep	United
03 Sep - 17 Sep	United
11 Sep - 19 Sep	United
02 Sep - 23 Sep	United
03 Sep - 24 Sep	United
09 Sep - 30 Sep	United
02 Sep - 09 Sep	United
10 Sep - 01 Oct	United
16 Sep - 07 Oct	United
17 Sep - 10 Oct	United
23 Sep - 13 Oct	United
24 Sep - 06 Oct	United
29 Sep - 06 Oct	Delta
30 Sep - 07 Oct	Delta

Also check the deals for one-way flights from Philadelphia to Singapore 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 Singapore in September from 789€

Return flights