Expect strict security at Heathrow. Ensure all liquids are in one small bag to avoid delays during manual screening.

Most accurate provider | eDreams 3 stars |
|---|---|
Most trusted provider | eDreams 3 stars |
Round-trip from | $604 (United Airlines) |
One-way from | $282 (Norse) |
Popular in | December |
Cheapest in | January |
Average price | $643 |
Good round-trip deal | $739 or less |
Good one-way deal | $611 or less |
Fly from
Fly to
Route
Depart
Return
Price
LondonPhiladelphia
LHR - PHL
LHRPHL
London Heathrow
Mon 1/26
10:15 am-1:30 pm
Nonstop8h 15m
Philadelphia
Mon 2/2
7:50 pm-7:50 am
Nonstop7h 00m
LondonPhiladelphia
LHR - PHL
LHRPHL
London Heathrow
Mon 3/2
10:15 am-1:15 pm
Nonstop8h 00m
Philadelphia
Mon 3/9
7:35 pm-6:35 am
Nonstop7h 00m
LondonPhiladelphia
LHR - PHL
LHRPHL
London Heathrow
Mon 1/26
11:45 am-11:13 pm
2 stops16h 28m
Philadelphia
Tue 2/24
9:41 am-8:45 am
1 stop18h 04m
LondonPhiladelphia
LHR - PHL
LHRPHL
London Heathrow
Wed 1/28
6:30 am-4:50 pm
2 stops15h 20m
Philadelphia
Mon 2/23
11:09 am-7:50 am
1 stop15h 41m
LondonPhiladelphia
LHR - PHL
LHRPHL
London Heathrow
Tue 1/27
6:30 am-4:50 pm
2 stops15h 20m
Philadelphia
Mon 2/23
6:00 am-6:50 am
1 stop19h 50m
LondonPhiladelphia
LHR - PHL
LHRPHL
London Heathrow
Mon 1/26
11:45 am-11:13 pm
2 stops16h 28m
Philadelphia
Mon 2/23
11:09 am-7:50 am
1 stop15h 41m
LondonPhiladelphia
LHR - PHL
LHRPHL
London Heathrow
Mon 1/26
11:45 am-11:13 pm
2 stops16h 28m
Philadelphia
Sun 2/22
8:06 pm-8:45 am
1 stop31h 39m
LondonPhiladelphia
LHR - PHL
LHRPHL
London Heathrow
Mon 1/26
11:45 am-11:13 pm
2 stops16h 28m
Philadelphia
Wed 2/25
2:31 pm-10:50 am
2 stops15h 19m
LondonPhiladelphia
LHR - PHL
LHRPHL
London Heathrow
Mon 1/26
8:25 am-3:40 pm
1 stop12h 15m
Philadelphia
Mon 2/2
7:50 pm-7:50 am
Nonstop7h 00m
LondonPhiladelphia
LHR - PHL
LHRPHL
London Heathrow
Fri 2/13
7:25 am-5:14 pm
1 stop14h 49m
Philadelphia
Sat 2/21
8:02 pm-10:50 am
1 stop9h 48m
| Provider | Price Accuracy | Trust Score* |
|---|---|---|
| Price Accuracy2 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*1 star | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy2 stars | Trust Score*2 stars | |
| Price Accuracy1 star | Trust Score*3 stars | |
| Price Accuracy2 stars | Trust Score*3 stars |
The best time to book flights from London to Philadelphia is 20 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.
Currently, March is the cheapest month in which you can book a flight from London to Philadelphia (average of $308). Flying from London to Philadelphia in July is currently the most expensive (average of $455). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.
When flying from London to Philadelphia, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.
The most flights from LON to PHL are scheduled on a Monday (10 on average). You will have fewer flight options on Monday, which is when the least amount of flights are scheduled (10 on average).
Dublin (DUB) – chosen by Cheapflights users on 71% of 1-stop itineraries from London to Philadelphia on Cheapflights.
Boston (BOS) is the most affordable 1-stop option, with an average round-trip price of $872.
Flights via Dublin (DUB) have the shortest average one-way travel time for 1-stop routes: 10h 23m.
Flights via Dublin (DUB) offer the fastest connection on this route, with an average layover time of 1h 48m.
About 17% of weekly flights between London and Philadelphia have experienced delays in the past year, with the average delay time being 174 minutes.
Historically, flights departing in the morning are less likely to be delayed, whereas flights leaving in the early afternoon tend to experience delays more often.
Wednesday tends to have the lowest number of delays on this route, whereas Thursday has historically faced a higher average of delays compared to other days of the week.
Over the last year, British Airways have had the lowest number of delays on this route, with just 15% of flights being delayed.
Boarding
Overall
Comfort
Entertainment
Crew
Food
Reviews
Dane,Jan 2026
TYS - IAD
Boarding
Overall
Comfort
Entertainment
Crew
Food
Reviews
Dane,Jan 2026
TYS - IAD
Boarding
Overall
Comfort
Entertainment
Crew
Food
Reviews
Dane,Jan 2026
TYS - IAD
Boarding
Overall
Comfort
Entertainment
Crew
Food
Reviews
Dane,Jan 2026
TYS - IAD
Boarding
Overall
Comfort
Entertainment
Crew
Food
Reviews
Dane,Jan 2026
TYS - IAD
Boarding
Overall
Comfort
Entertainment
Crew
Food
Reviews
Dane,Jan 2026
TYS - IAD
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$429 | Average$741 | FlexibilityNo cancel fee | On-time77% | |
| Cheapest$592 | Average$814 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$610 | Average$793 | FlexibilityNo cancel fee | On-time70% | |
| Cheapest$670 | Average$1,182 | FlexibilityNo cancel fee | On-timeN/A |