Expect long security queues at IAD, especially in the afternoon and evening. Arrive early to navigate the check-in and security process smoothly.

Most accurate provider | Gotogate 3 stars |
|---|---|
Most trusted provider | Gotogate 3 stars |
Round-trip from | $567 (CrystalTravel) |
One-way from | $198 (Kiwi.com) |
Popular in | December |
Cheapest in | September |
Average price | $986 |
Good round-trip deal | $642 or less |
Good one-way deal | $435 or less |
Fly from
Fly to
Route
Depart
Return
Price
Washington, D.C.London
IAD - LHR
IADLHR
Washington, D.C. Dulles Intl
Thu 2/26
8:30 pm-4:25 pm
2 stops14h 55m
London Heathrow
Thu 3/5
10:20 am-5:15 pm
1 stop11h 55m
Washington, D.C.London
IAD - LGW
IADLGW
Washington, D.C. Dulles Intl
Thu 1/29
5:30 pm-9:50 am
1 stop11h 20m
London Gatwick
Sun 2/1
9:05 am-9:00 pm
2 stops16h 55m
Washington, D.C.London
IAD - LTN
IADLTN
Washington, D.C. Dulles Intl
Mon 1/12
8:30 pm-6:15 pm
2 stops16h 45m
London Luton
Sun 1/18
8:30 am-3:20 pm
2 stops35h 50m
Washington, D.C.London
IAD - LGW
IADLGW
Washington, D.C. Dulles Intl
Fri 1/23
10:30 pm-3:45 pm
1 stop12h 15m
London Gatwick
Sat 1/31
10:10 am-9:00 pm
2 stops39h 50m
Washington, D.C.London
IAD - LGW
IADLGW
Washington, D.C. Dulles Intl
Sat 1/24
5:30 pm-9:50 am
1 stop11h 20m
London Gatwick
Sat 1/31
10:10 am-9:00 pm
2 stops39h 50m
Washington, D.C.London
IAD - LHR
IADLHR
Washington, D.C. Dulles Intl
Sat 1/24
8:30 pm-6:50 pm
2 stops17h 20m
London Heathrow
Tue 2/3
9:05 pm-5:15 pm
2 stops25h 10m
BaltimoreLondon
BWI - LTN
BWILTN
Baltimore/Washington
Wed 2/4
7:40 pm-12:55 pm
1 stop12h 15m
London Luton
Wed 2/11
8:00 am-6:40 pm
1 stop15h 40m
BaltimoreLondon
BWI - LTN
BWILTN
Baltimore/Washington
Wed 2/25
7:40 pm-12:55 pm
1 stop12h 15m
London Luton
Mon 3/2
8:00 am-6:40 pm
1 stop15h 40m
Washington, D.C.London
IAD - LGW
IADLGW
Washington, D.C. Dulles Intl
Wed 1/14
6:10 pm-5:50 pm
2 stops18h 40m
London Gatwick
Mon 1/19
6:40 pm-4:40 pm
1 stop27h 00m
Washington, D.C.London
IAD - LHR
IADLHR
Washington, D.C. Dulles Intl
Sat 2/14
10:15 pm-10:50 am
Nonstop7h 35m
London Heathrow
Sun 3/1
6:50 am-2:35 pm
1 stop12h 45m
| 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 Accuracy2 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy2 stars | Trust Score*3 stars | |
| Price Accuracy2 stars | Trust Score*2 stars | |
| Price Accuracy- | Trust Score*1 star |
The best time to book flights from Washington, D.C. to London is 37 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 Washington, D.C. to London (average of $31). Flying from Washington, D.C. to London in June is currently the most expensive (average of $728). 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.
A simple way to save on the total cost of your ticket is to fly from Washington, D.C. to London in the afternoon. If you’re flexible enough to do this you can expect to save up to 21% on your trip compared to booking a flight at noon.
Travelers seeking maximum savings on their Washington, D.C. to London flight should consider departing on Sunday afternoons when fares are most often at their lowest. Friday at noon flights should be avoided if possible as fares are typically the most expensive at this time.
The most flights from WAS to LON are scheduled on a Monday (26 on average). You will have fewer flight options on Sunday, which is when the least amount of flights are scheduled (19 on average).
Reykjavik (KEF) – chosen by Cheapflights users on 68% of 1-stop itineraries from Washington, D.C. to London 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 Montreal (YUL) offer the fastest connection on this route, with an average layover time of 1h 24m.
About 21% of weekly flights between Washington, D.C. and London have experienced delays in the past year, with the average delay time being 159 minutes.
Historically, flights departing in the morning are less likely to be delayed, whereas flights leaving in the evening tend to experience delays more often.
Monday tends to have the lowest number of delays on this route, whereas Saturday has historically faced a higher average of delays compared to other days of the week.
Over the last year, Virgin Atlantic have had the lowest number of delays on this route, with just 15% of flights being delayed.
Boarding
Food
Comfort
Entertainment
Overall
Crew
Reviews
Michelle,Dec 2025
DEN - MKE
Boarding
Food
Comfort
Entertainment
Overall
Crew
Reviews
Michelle,Dec 2025
DEN - MKE
Boarding
Food
Comfort
Entertainment
Overall
Crew
Reviews
Michelle,Dec 2025
DEN - MKE
Boarding
Food
Comfort
Entertainment
Overall
Crew
Reviews
Michelle,Dec 2025
DEN - MKE
Boarding
Food
Comfort
Entertainment
Overall
Crew
Reviews
Michelle,Dec 2025
DEN - MKE
Boarding
Food
Comfort
Entertainment
Overall
Crew
Reviews
Michelle,Dec 2025
DEN - MKE
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$31 | Average$811 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$369 | Average$511 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$395 | Average$566 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$429 | Average$641 | FlexibilityNo cancel fee | On-time76% | |
| Cheapest$429 | Average$593 | FlexibilityNo cancel fee | On-time77% | |
| Cheapest$447 | Average$1,061 | FlexibilityNo cancel fee | On-time76% | |
| Cheapest$497 | Average$842 | FlexibilityNo cancel fee | On-time72% | |
| Cheapest$497 | Average$846 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$506 | Average$834 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$520 | Average$615 | FlexibilityNo cancel fee | On-time75% |