Route brief · LON → WAS
London → Washington
$432
−26% vs typical
seasonal median $580 · difference $148
May 20 '27 – May 30 '27 · 10 nights
Icelandair1 stop
- Usual monthly lows
- $516–$578
- Board rank
- Stronger than 71%
- Route sample
- 4 observed months
Cached fare — the booking search re-prices live before you pay.
Destination briefWASWashingtonFree museums by the dozen, and three airports competing hard enough to keep transatlantic fares honest.Best windowApr–May · Sep–OctAirportsDulles (IAD) · Reagan National (DCA) · Baltimore (BWI)All routes into WashingtonWhen this route gets cheap.
Cached-fare history: across 4 months, May is the cheapest for LON → WAS. Best time to be there: Apr–May · Sep–Oct.
Fares bottom out in May around $432 and peak in October near $602 — a $170 spread across the 4 months we track. The cheapest itinerary we are tracking makes one stop and takes about 9.5 hours outbound, on a 10-night trip — ticketed under Icelandair, which on a connecting fare need not operate every leg. At $432 for 5,898 km each way, that works out to about $37 per 1,000 km flown. That is below the $39 typical of medium-haul fares here. Of the 18 departure cities we track at a similar distance from Washington, this is the cheapest right now — 5% under the next one, Stockholm. That puts it in the cheaper half of the 12 routes of similar length we watch out of London, where the middle fare is $510.
The one day we hold a cached fare for
Tap a date → live search
The median cached fare across this calendar is 15% lower than when tracking began on Aug 8 — $797 then versus $679 now, across 5 recorded snapshots. This is a calendar-level trend, so an individual deal above can be lower. The lowest single day we have seen here is $494, on Oct 31.
These are the only days we have a cached price for on this route so far — not the only days it flies. The search above covers any date.
Cheapest in May · around $432
26% below the $580 typical fare
Cheapest round-trip fare found per month · London → Washington · cached-price history
Route facts
- Airports
- Heathrow (LHR) · Gatwick (LGW) · Stansted (STN) · Luton (LTN) ↔ Dulles (IAD) · Reagan National (DCA) · Baltimore (BWI)
- Flight time
- ~9.5 hours outbound
- Distance
- ~5,898 km each way
- Typical price
- $580 round-trip (seasonal median)
- Airlines on the board
- Icelandair
- Itineraries
- Connections on current fares
- Best months to visit
- Apr–May · Sep–Oct
LON → WAS, answered.
Is $432 a good price for London to Washington?
Yes — the seasonal median for this route is around $580 round-trip. At $432 you're 26% below that, saving about $148, which we rate good for this route.
What is the cheapest month to fly from London to Washington?
Across 4 months of cached-fare history, May comes out cheapest on this route. The best months to actually be in Washington are Apr–May · Sep–Oct — when those overlap, that's your window.
How far in advance should I book LON → Washington?
We do not publish a number for this, because we cannot measure it yet. Answering it honestly means watching the same departure date on this route over many weeks as it approaches, and that archive is still filling up — so any "book N days ahead" figure here would be borrowed from somewhere else rather than measured. What we can measure is which month is cheap: across 4 months of cached fares, May comes out lowest on this route. See /guides/what-moves-a-flight-price/ for what does move a fare.
Are there nonstop flights from London to Washington?
The current cheapest fares involve a connection, ticketed under Icelandair. Nonstop options exist on many dates at higher prices — check the live search for your exact dates.
Are these prices guaranteed?
No — these are cached fares found on real searches (this one on September 1). Airlines reprice constantly, so the booking search re-checks the live price before you pay. Fresher finds are far more likely to still be available.
Next step
Sleeping in Washington?
Lock the flight first — then compare stays for May 20 '27 – May 30 '27 · 10 nights.
Browse hotels ↗
Missed it?
Cached fares expire. This route has a feed of its own — follow it and the next LON → WAS drop reaches you as soon as we find it.
Follow LON → WAS