AirHint found the following cheapest return flights from Portland (PDX) to London (STN) in March 2026 (see full year).

Return flights

16 Mar - 23 Mar	Icelandair
24 Mar - 31 Mar	Icelandair
10 Mar - 09 Apr	Icelandair
17 Mar - 24 Mar	Icelandair
09 Mar - 16 Mar	Icelandair
29 Mar - 17 Apr	Hawaiian Airlines
09 Mar - 19 Mar	Icelandair
16 Mar - 30 Mar	Icelandair
29 Mar - 12 Apr	Hawaiian Airlines
29 Mar - 13 Apr	Hawaiian Airlines
15 Mar - 23 Mar	KLM
08 Mar - 18 Mar	Frontier Airlines
06 Mar - 16 Mar	Hawaiian Airlines
15 Mar - 22 Mar	Frontier Airlines
22 Mar - 06 Apr	Hawaiian Airlines
22 Mar - 05 Apr	Air Canada

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

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 March from $511

Return flights