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

Return flights

03 Dec - 12 Dec	British Airways	direct
03 Dec - 10 Dec	British Airways	direct
09 Dec - 16 Dec	United
11 Dec - 25 Dec	Air Canada
04 Dec - 11 Dec	United
14 Dec - 22 Dec	Air Canada
14 Dec - 21 Dec	British Airways
14 Dec - 29 Dec	Air Canada
17 Dec - 24 Dec	British Airways
25 Dec - 08 Jan	United
28 Dec - 05 Jan	Air Canada
14 Dec - 22 Dec	Finnair	direct
06 Dec - 06 Jan	United
15 Dec - 06 Jan	United
28 Dec - 04 Jan	Air Canada
13 Dec - 01 Jan	Delta
13 Dec - 06 Jan	Delta
29 Dec - 05 Jan	United
22 Dec - 01 Jan	Delta
14 Dec - 05 Jan	United

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 544€

Return flights