AirHint found the following cheapest return flights from Portland (PDX) to London (LGW) in December 2025 (see full year).

Return flights

08 Dec - 21 Dec	Icelandair
16 Dec - 21 Dec	Icelandair
14 Dec - 21 Dec	Icelandair
23 Dec - 17 Jan	Sun Country Airlines
08 Dec - 29 Dec	Icelandair
14 Dec - 29 Dec	Sun Country Airlines
13 Dec - 29 Dec	Icelandair
21 Dec - 31 Dec	Sun Country Airlines
21 Dec - 05 Jan	Sun Country Airlines
24 Dec - 02 Jan	Alaska Airlines
22 Dec - 16 Jan	Icelandair
20 Dec - 31 Dec	Sun Country Airlines
19 Dec - 28 Dec	Alaska Airlines
14 Dec - 30 Dec	Air Canada
26 Dec - 02 Jan	Alaska Airlines
26 Dec - 03 Jan	Alaska Airlines

Also check the deals for one-way flights from Portland to London in December.

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 Portland to London in December from $622

Return flights