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 | $560 (Mytrip) |
One-way from | $186 (Kiwi.com) |
Popular in | June |
Cheapest in | September |
Average price | $744 |
Good round-trip deal | $671 or less |
Good one-way deal | $442 or less |
Fly from
Fly to
Route
Depart
Return
Price
Washington, D.C.London
IAD - LTN
IADLTN
Washington, D.C. Dulles Intl
Mon 2/2
9:45 am-8:10 pm
2 stops29h 25m
London Luton
Mon 2/9
8:50 pm-8:54 pm
3 stops29h 04m
Washington, D.C.London
IAD - LTN
IADLTN
Washington, D.C. Dulles Intl
Sat 1/24
8:30 pm-8:55 pm
2 stops19h 25m
London Luton
Wed 1/28
9:45 pm-5:15 pm
2 stops24h 30m
Washington, D.C.London
IAD - LTN
IADLTN
Washington, D.C. Dulles Intl
Fri 1/9
7:40 pm-3:25 pm
2 stops14h 45m
London Luton
Wed 1/14
6:50 am-6:30 pm
2 stops16h 40m
Washington, D.C.London
IAD - STN
IADSTN
Washington, D.C. Dulles Intl
Sat 1/31
7:40 pm-1:20 pm
2 stops12h 40m
London Stansted
Sun 2/8
8:30 am-6:30 pm
2 stops15h 00m
Washington, D.C.London
IAD - LHR
IADLHR
Washington, D.C. Dulles Intl
Wed 12/31
10:20 pm-10:50 am
Nonstop7h 30m
London Heathrow
Wed 1/14
9:00 am-4:35 pm
1 stop12h 35m
Washington, D.C.London
IAD - LHR
IADLHR
Washington, D.C. Dulles Intl
Wed 11/12
10:20 pm-10:50 am
Nonstop7h 30m
London Heathrow
Tue 11/25
6:20 am-4:35 pm
1 stop15h 15m
Washington, D.C.London
IAD - LHR
IADLHR
Washington, D.C. Dulles Intl
Mon 12/8
10:20 pm-10:50 am
Nonstop7h 30m
London Heathrow
Mon 12/15
10:00 am-4:05 pm
1 stop11h 05m
Washington, D.C.London
IAD - LHR
IADLHR
Washington, D.C. Dulles Intl
Wed 11/26
7:01 am-5:25 am
2 stops17h 24m
London Heathrow
Tue 12/2
8:55 am-4:35 pm
1 stop12h 40m
BaltimoreLondon
BWI - LGW
BWILGW
Baltimore/Washington
Wed 11/12
7:40 pm-10:55 am
1 stop10h 15m
London Gatwick
Tue 11/18
11:55 am-6:40 pm
1 stop11h 45m
BaltimoreLondon
BWI - LHR
BWILHR
Baltimore/Washington
Tue 12/2
12:19 pm-6:25 am
1 stop13h 06m
London Heathrow
Wed 2/25
11:30 am-10:55 pm
2 stops16h 25m
| 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 Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*2 stars | |
| Price Accuracy- | Trust Score*1 star |
The best time to book flights from Washington, D.C. to London is 47 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 $744). 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 16% 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 Saturday (26 on average). You will have fewer flight options on Monday, which is when the least amount of flights are scheduled (18 on average).
Reykjavik (KEF) – chosen by Cheapflights users on 73% 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 Reykjavik (KEF) offer the fastest connection on this route, with an average layover time of 1h 23m.
Food
Overall
Crew
Boarding
Comfort
Entertainment
Reviews
Sebrena,Oct 2025
IAH - RSW
Food
Overall
Crew
Boarding
Comfort
Entertainment
Reviews
Sebrena,Oct 2025
IAH - RSW
Food
Overall
Crew
Boarding
Comfort
Entertainment
Reviews
Sebrena,Oct 2025
IAH - RSW
Food
Overall
Crew
Boarding
Comfort
Entertainment
Reviews
Sebrena,Oct 2025
IAH - RSW
Food
Overall
Crew
Boarding
Comfort
Entertainment
Reviews
Sebrena,Oct 2025
IAH - RSW
Food
Overall
Crew
Boarding
Comfort
Entertainment
Reviews
Sebrena,Oct 2025
IAH - RSW
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$31 | Average$799 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$369 | Average$522 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$395 | Average$604 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$397 | Average$900 | FlexibilityNo cancel fee | On-time76% | |
| Cheapest$424 | Average$596 | FlexibilityNo cancel fee | On-time77% | |
| Cheapest$432 | Average$648 | FlexibilityNo cancel fee | On-time76% | |
| Cheapest$497 | Average$851 | FlexibilityNo cancel fee | On-time72% | |
| Cheapest$497 | Average$850 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$506 | Average$837 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$520 | Average$654 | FlexibilityNo cancel fee | On-time75% |