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

Return flights

02 Dec - 09 Dec	British Airways
28 Dec - 11 Jan	Delta
07 Dec - 14 Dec	British Airways	direct
12 Dec - 19 Dec	United
28 Dec - 11 Jan	British Airways	direct
17 Dec - 24 Dec	British Airways
14 Dec - 30 Dec	United
15 Dec - 30 Dec	United
14 Dec - 29 Dec	United
17 Dec - 22 Dec	Iberia
15 Dec - 31 Dec	United
14 Dec - 29 Dec	Finnair	direct
14 Dec - 04 Jan	Air Canada
14 Dec - 04 Jan	British Airways	direct
27 Dec - 03 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 480€

Return flights