How long is the DL21 flight from London to Seattle?

The timetable allows 10 h 30 min. London to Seattle is 7,701 km (4,785 mi).

Which terminal does DL21 use?

It usually leaves from Terminal 3 at London Heathrow Airport (LHR). Check the flight card above for today's terminal and gate.

What other flight numbers does DL21 have?

Also listed as DAL21 (Delta Air Lines' ICAO code) and DL 21.

Can I get compensation if DL21 is delayed or cancelled?

Up to £520 per passenger may be due under UK261 when it arrives 3 or more hours late or is cancelled, unless the cause was outside the airline's control. Departing the UK, this flight is covered by UK261.

DL21 Flight Status Delta Air Lines: London to Seattle (DAL21)

Delta Air Lines DL 21

Scheduled in 2h12'

LHR London

Scheduled: 12:20
Estimated: 12:20

Terminal: 3 | Gate: 29

Departure: Sat, Nov 14, 2026 · local time GMT

London Heathrow Airport (LHR)

All LHR Departures >

SEA Seattle

Scheduled: 14:50
Estimated
Delay

Gate: A8

Arrival: Sat, Nov 14, 2026 · local time PST

Seattle Tacoma International Airport (SEA)

All SEA Arrivals >

Departs in 2h 12m 0%

LHR 12:20 SEA 14:50

7,701 km (4,785 mi) to fly

Estimated position based on departure and arrival times, not live tracking. Times are local at each airport.

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Distance: 7701 km / 4785 miles · Scheduled Duration: 10:30 · Typical Duration: 09:50

Flight issues? Claim up to £520 >

DL 21 Flight Status & Schedule Delta Air Lines London to Seattle

Date	From	To	Departure	Arrival	Status	Details
Nov 14	LHR	SEA	12:20	14:50	Scheduled	Track >
Nov 13	LHR	SEA	12:51	14:55	Landed	Track >
Nov 12	LHR	SEA	12:38	14:49	Landed	Track >
Nov 11	LHR	SEA	12:36	14:21	Landed	Track >
Nov 10	LHR	SEA	12:54	14:33	Landed	Track >
Nov 09	LHR	SEA	14:22	16:30	Delayed	Track >
Nov 08	LHR	SEA	12:55	15:16	Landed Late	Track >
Nov 07	LHR	SEA	12:32	14:24	Landed	Track >
Nov 06	LHR	SEA	13:18	15:04	Landed	Track >
Nov 05	LHR	SEA	12:30	13:51	Landed	Track >

Delta Air Lines operates DL 21 from London to Seattle, a 7,701 km (4,785 mi) trip, daily. The timetable allows 10 h 30 min, but the flight usually takes about 9 h 50 min, so it often makes up time. Today's flight is scheduled to leave at 12:20 and arrive at 14:50 local time.

< All London LHR Departures All Seattle SEA Arrivals >

About DL 21

Delta Air Lines Flight DL21 connects London, United Kingdom to Seattle, United States, taking off from London Heathrow Airport LHR and landing at Seattle Tacoma International Airport SEA.

Route: London Heathrow Airport LHR to Seattle Tacoma International Airport SEA
Distance: 7,701 km (4,785 mi)
Typical flight time: 9 h 50 min
Flies: Daily
On time: 7 of the last 8
Average delay when late: 26 min
Usually departs from: Terminal 3

Departing the UK, this flight is covered by UK261. Compensation of up to £520 per passenger can apply when it arrives 3 or more hours late or is cancelled.

DL 21 FAQ

How long is the DL21 flight from London to Seattle?: The timetable allows 10 h 30 min. London to Seattle is 7,701 km (4,785 mi).
How often is DL21 from London to Seattle late?: 1 of the last 8 flights arrived 15 or more minutes late; when late, by 26 minutes on average.
When was the latest DL21 flight from London to Seattle?: The latest DL21 was the 12:20 (local time) departure from London on 13 November 2026; it landed 5 minutes late.
Which days does DL21 fly from London to Seattle?: Daily: it was scheduled on each of the last 7 days.
Which terminal does DL21 use?: It usually leaves from Terminal 3 at London Heathrow Airport (LHR). Check the flight card above for today's terminal and gate.
What other flight numbers does DL21 have?: Also listed as DAL21 (Delta Air Lines' ICAO code) and DL 21.
Can I get compensation if DL21 is delayed or cancelled?: Up to £520 per passenger may be due under UK261 when it arrives 3 or more hours late or is cancelled, unless the cause was outside the airline's control. Departing the UK, this flight is covered by UK261.

DL21 and London LHR to Seattle SEA Flights

Other flights departing from London LHR: FI451, B620, BA169

Other flights arriving at Seattle SEA: AF76, JX32, BA49, DL332

All flights connecting London LHR to Seattle SEA.