For evening departures, expect crowded check-in areas at IAD. Plan extra time for security and navigating the terminal layout.

Round-trip from | $491 (Gotogate) |
|---|---|
One-way from | $235 (Mytrip) |
Popular in | June |
Cheapest in | August |
Average price | $661 |
Good round-trip deal | $635 or less |
Good one-way deal | $384 or less |
Fly from
Fly to
Route
Depart
Return
Price
Washington, D.C.London
IAD - LHR
IADLHR
Washington, D.C. Dulles Intl
Wed 3/11
12:30 pm-9:20 am
2 stops16h 50m
London Heathrow
Thu 3/19
6:40 am-6:15 pm
2 stops15h 35m
Washington, D.C.London
IAD - LHR
IADLHR
Washington, D.C. Dulles Intl
Sat 1/24
12:30 pm-9:20 am
2 stops15h 50m
London Heathrow
Sun 2/1
9:05 pm-5:15 pm
2 stops25h 10m
BaltimoreLondon
BWI - LHR
BWILHR
Baltimore/Washington
Fri 10/24
8:30 pm-11:55 am
1 stop10h 25m
London Heathrow
Thu 11/6
8:35 pm-6:40 pm
1 stop27h 05m
BaltimoreLondon
BWI - LHR
BWILHR
Baltimore/Washington
Mon 9/29
8:30 pm-11:55 am
1 stop10h 25m
London Heathrow
Wed 10/15
1:05 pm-7:25 pm
1 stop11h 20m
BaltimoreLondon
BWI - LHR
BWILHR
Baltimore/Washington
Thu 10/2
8:30 pm-11:55 am
1 stop10h 25m
London Heathrow
Sun 10/5
9:25 pm-7:25 pm
1 stop27h 00m
Washington, D.C.London
IAD - LHR
IADLHR
Washington, D.C. Dulles Intl
Wed 11/26
6:20 pm-6:40 am
Nonstop7h 20m
London Heathrow
Mon 12/8
1:45 pm-4:40 pm
1 stop31h 55m
Washington, D.C.London
IAD - LHR
IADLHR
Washington, D.C. Dulles Intl
Wed 2/4
12:30 pm-9:20 am
2 stops15h 50m
London Heathrow
Mon 2/9
10:20 am-5:15 pm
1 stop11h 55m
Washington, D.C.London
IAD - LHR
IADLHR
Washington, D.C. Dulles Intl
Wed 1/14
6:20 pm-6:40 am
Nonstop7h 20m
London Heathrow
Tue 1/20
6:50 am-2:35 pm
1 stop12h 45m
Washington, D.C.London
IAD - LHR
IADLHR
Washington, D.C. Dulles Intl
Wed 10/1
5:50 pm-6:20 am
Nonstop7h 30m
London Heathrow
Wed 10/15
11:30 am-7:15 pm
1 stop12h 45m
Washington, D.C.London
IAD - LHR
IADLHR
Washington, D.C. Dulles Intl
Mon 9/29
5:50 pm-6:20 am
Nonstop7h 30m
London Heathrow
Wed 10/15
11:30 am-7:15 pm
1 stop12h 45m
Booking 63 days in advance of your planned departure date is, on average, the best time to get cheap flights from Washington, D.C. to London Heathrow Airport. The general trend is that the closer you book to the departure date, the more expensive your flight will be.
Currently, November is the cheapest month in which you can book a flight from Washington, D.C. to London Heathrow Airport (average of $661). Flying from Washington, D.C. to London Heathrow Airport in June is currently the most expensive (average of $1,097). 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.
It’s typically best to fly out from Washington, D.C. to London Heathrow Airport in the afternoon. Doing so could potentially save you 4% on the flight price compared to flying in the morning, which is usually more expensive.
Travelers seeking maximum savings on their Washington, D.C. to London Heathrow Airport flight should consider departing on Wednesday mornings when fares are most often at their lowest. Saturday at noon flights should be avoided if possible as fares are typically the most expensive at this time.
The most flights from WAS to LHR are scheduled on a Monday (28 on average). You will have fewer flight options on Thursday, which is when the least amount of flights are scheduled (20 on average).
Reykjavik (KEF) – chosen by Cheapflights users on 63% of 1-stop itineraries from Washington, D.C. to London Heathrow Airport on Cheapflights.
Dublin (DUB) is the most affordable 1-stop option, with an average round-trip price of $479.
Flights via Montreal (YUL) have the shortest average one-way travel time for 1-stop routes: 9h 20m.
Flights via Reykjavik (KEF) offer the fastest connection on this route, with an average layover time of 1h 20m.
Comfort
Overall
Food
Boarding
Crew
Entertainment
Reviews
Thomas,Mar 2025
SFO - TPE
Comfort
Overall
Food
Boarding
Crew
Entertainment
Reviews
Thomas,Mar 2025
SFO - TPE
Comfort
Overall
Food
Boarding
Crew
Entertainment
Reviews
Thomas,Mar 2025
SFO - TPE
Comfort
Overall
Food
Boarding
Crew
Entertainment
Reviews
Thomas,Mar 2025
SFO - TPE
Comfort
Overall
Food
Boarding
Crew
Entertainment
Reviews
Thomas,Mar 2025
SFO - TPE
Comfort
Overall
Food
Boarding
Crew
Entertainment
Reviews
Thomas,Mar 2025
SFO - TPE
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$31 | Average$806 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$372 | Average$471 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$421 | Average$797 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$424 | Average$597 | FlexibilityNo cancel fee | On-time77% | |
| Cheapest$433 | Average$573 | FlexibilityNo cancel fee | On-time76% | |
| Cheapest$441 | Average$601 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$447 | Average$812 | FlexibilityNo cancel fee | On-time76% | |
| Cheapest$497 | Average$851 | FlexibilityNo cancel fee | On-time72% | |
| Cheapest$497 | Average$854 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$506 | Average$858 | FlexibilityNo cancel fee | On-time69% |