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

Return flights

01 Dec - 09 Dec	Icelandair
04 Dec - 08 Dec	Icelandair
02 Dec - 08 Dec	Icelandair
02 Dec - 06 Dec	Icelandair
01 Dec - 15 Dec	Icelandair
05 Dec - 10 Dec	Air Canada
15 Dec - 10 Jan	Hawaiian Airlines
07 Dec - 14 Dec	Alaska Airlines
15 Dec - 29 Dec	Alaska Airlines
14 Dec - 28 Dec	Icelandair
20 Dec - 10 Jan	Icelandair
22 Dec - 17 Jan	Icelandair
02 Dec - 27 Dec	Hawaiian Airlines
21 Dec - 05 Jan	Alaska Airlines
23 Dec - 01 Jan	Air Canada
22 Dec - 01 Jan	Icelandair
20 Dec - 02 Jan	Alaska Airlines
22 Dec - 04 Jan	Icelandair

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 $488

Return flights