August is the cheapest month to fly this route, with average fares around $1045 round trip.
Average round-trip fares by departure month, based on current availability.
| Month | Avg Price | Lowest | Relative Cost | |
|---|---|---|---|---|
| May 2026 | $1161 | $1036 | ||
| June 2026 | $1238 | $1050 | Peak | |
| July 2026 | $1166 | $1074 | ||
| August 2026 | $1045 | $855 | Best |
Departing on Tuesday offers the lowest average fares at $1124. Thursday departures are the most expensive at $1260, a difference of $136.
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 Philadelphia to London is August, with average round-trip fares around $1045. The lowest fare found in August is $855.
Tuesday departures are the cheapest, averaging $1124 round trip. The most expensive day is Thursday at $1260.
Based on current pricing trends, booking for August travel offers the best value. Avoid June if possible, as fares average $1238 compared to $1045 in the cheapest month. July is a solid middle-ground option at $1166.
Flying in August instead of June can save you approximately $193 per round trip. The cheapest month averages $1045 while the most expensive averages $1238.
Airlines, flight times, price calendar, and more for Philadelphia to London
View PHL → LHR Details