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

Return flights

01 Dec - 12 Dec	Icelandair
08 Dec - 14 Dec	Icelandair
02 Dec - 06 Dec	Icelandair
03 Dec - 08 Dec	British Airways	direct
05 Dec - 10 Dec	British Airways
31 Dec - 24 Jan	British Airways
04 Dec - 08 Dec	Icelandair
05 Dec - 07 Dec	British Airways	direct
29 Dec - 24 Jan	KLM
01 Dec - 15 Dec	Icelandair
23 Dec - 17 Jan	Air Canada
05 Dec - 27 Dec	British Airways
10 Dec - 19 Dec	KLM
12 Dec - 05 Jan	Air Canada
22 Dec - 10 Jan	KLM
20 Dec - 10 Jan	Delta
21 Dec - 10 Jan	Air Canada
18 Dec - 10 Jan	Alaska Airlines
25 Dec - 01 Jan	Air Canada
12 Dec - 04 Jan	Hawaiian 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 $490

Return flights