AirHint found the following cheapest return flights from Philadelphia (PHL) to London (LGW) in January 2026 (see full year).

Return flights

12 Jan - 22 Jan	Frontier Airlines
27 Jan - 09 Feb	Frontier Airlines
12 Jan - 20 Jan	Air Canada
13 Jan - 22 Jan	Spirit Airlines
12 Jan - 07 Feb	Frontier Airlines
16 Jan - 20 Jan	Air Canada
13 Jan - 20 Jan	Frontier Airlines
10 Jan - 20 Jan	Frontier Airlines
30 Jan - 07 Feb	Frontier Airlines
16 Jan - 24 Jan	Frontier Airlines
14 Jan - 07 Feb	TAP
10 Jan - 14 Jan	Frontier Airlines
07 Jan - 31 Jan	Spirit Airlines
23 Jan - 14 Feb	TAP

Also check the deals for one-way flights from Philadelphia to London in January.

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 London in January from $492

Return flights