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

Return flights

09 Mar - 15 Mar	Icelandair
16 Mar - 01 Apr	Icelandair
01 Mar - 13 Mar	Finnair	direct
02 Mar - 10 Mar	Finnair
01 Mar - 10 Mar	Virgin Atlantic
02 Mar - 11 Mar	Delta
08 Mar - 19 Mar	Virgin Atlantic
29 Mar - 17 Apr	Delta
01 Mar - 09 Mar	Air Canada
09 Mar - 16 Mar	Icelandair
23 Mar - 07 Apr	Air Canada
16 Mar - 02 Apr	American Airlines	direct
29 Mar - 17 Apr	American Airlines	direct
01 Mar - 07 Mar	Virgin Atlantic
01 Mar - 15 Mar	Delta
27 Mar - 10 Apr	Finnair	direct
29 Mar - 12 Apr	Virgin Atlantic
23 Mar - 06 Apr	Air Canada
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.

Book a cheap hotel in London

Cheap car rent in London

Cheapest return flights from Portland to London in March from $494

Return flights