August is the cheapest month to fly this route, with average fares around $1080 round trip.
Average round-trip fares by departure month, based on current availability.
| Month | Avg Price | Lowest | Relative Cost | |
|---|---|---|---|---|
| May 2026 | $1219 | $1091 | ||
| June 2026 | $1343 | $1120 | Peak | |
| July 2026 | $1219 | $1129 | ||
| August 2026 | $1080 | $928 | Best |
Departing on Sunday offers the lowest average fares at $1226. Friday departures are the most expensive at $1292, a difference of $66.
The best time to fly is August. Set up an alert and we'll notify you when prices drop.
Get Started Free →The cheapest month to fly from Portland to London is August, with average round-trip fares around $1080. The lowest fare found in August is $928.
Sunday departures are the cheapest, averaging $1226 round trip. The most expensive day is Friday at $1292.
Based on current pricing trends, booking for August travel offers the best value. Avoid June if possible, as fares average $1343 compared to $1080 in the cheapest month. July is a solid middle-ground option at $1219.
Flying in August instead of June can save you approximately $263 per round trip. The cheapest month averages $1080 while the most expensive averages $1343.
Airlines, flight times, price calendar, and more for Portland to London
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