Flight time & jet lag: Seoul to London

Seoul to London: Route overview

This westbound long-haul route from Seoul to London spans 8,861 km, with the 10h 21m to 11h 38m flight pushing your day 9 hours longer rather than shorter. At 9 time zones crossed westbound, this is among the most demanding routes for jet lag. Full adjustment typically requires 6 days of deliberate sleep and light management. Both cities sit at similar temperate latitudes, meaning daylight patterns will feel familiar upon arrival — a helpful factor for circadian adjustment.

What makes the Seoul–London route different

While westbound travel is generally easier than eastbound (your day gets longer rather than shorter), crossing 9 time zones still creates substantial disruption. The advantage is that most people find it easier to stay awake past their usual bedtime than to fall asleep earlier.

Arrival strategy for London

Flying west to London gains you 9 hours, extending your arrival day. At 18:00 local time, your body will think it is 03:00 — meaning you will feel ready for sleep well before the local bedtime. Counter this by getting bright light in the late afternoon and early evening. Eat dinner at the local time, stay physically active, and push your bedtime to at least 21:00 local. Avoid morning light before 08:00 on the first few days, as this would advance your clock in the wrong direction.

Circadian rhythm analysis: Seoul → London

When you arrive in London, your circadian rhythm is still running on Seoul time. At 09:00 London time, your body reads 18:00 — evening on your internal clock. You will feel an increasing pull toward sleep as the local morning progresses. The main westbound challenge is that by 22:00 local, your body clock reads 07:00 — past your natural bedtime. You will likely feel premature sleepiness in the late afternoon or early evening. Your circadian system adjusts at roughly 1 to 1.5 hours per day, so expect 6 days for full alignment.

Your body clock in London (day 1)

How your body clock maps to local time upon arrival, before any adjustment.

Pre-departure preparation

For this 9-hour westward shift to London, start 4 days before departure by delaying your bedtime by 135 minutes each night. Seek bright light in the evening hours to help push your clock later. On the flight, try to stay awake if arriving during London's daytime. This gradual shift can significantly ease your transition upon arrival.

Your first 72 hours in London

Day 1 in London: Your body is ~9 hours off local time. Stay active and seek afternoon sunlight. Push bedtime to at least 21:00 local. Eat at local mealtimes even if not hungry. Caffeine is fine before 16:00, not after. Day 2: ~8 hours off. Continue late afternoon (15:00–18:00) light exposure. Sleep quality should improve. Day 3: ~6 hours off. Noticeable improvement. Maintain light and meal timing discipline.

Recovery timeline

Full circadian adjustment for the Seoul → London route typically takes 6 days, based on the body's natural adaptation rate of ~1 to 1.5 hours per day for westbound travel. During this period, expect gradually improving sleep quality, with the most noticeable symptoms (fatigue, difficulty concentrating, appetite changes) during the first 3 days. By day 6, most travelers report feeling fully synchronized with London's schedule.

Route Planner

Adjust departure date for DST-accurate results.

Jet lag adjustment plan: Seoul → London

Significant jet lag. Allow 4–7 days for full adjustment. Plan sleep and light exposure carefully.

Business hours: Seoul vs London

Seasonal and climate factors

Flight times between Seoul and London can vary by 15–30 minutes seasonally due to shifting wind patterns along this long-haul corridor. London at 51°N experiences moderate seasonal daylight variation. Summer offers longer evenings useful for westward adjustment, while winter's earlier sunsets support eastward adjustment schedules.

How the Seoul–London flight time is estimated

The 10h 21m to 11h 38m estimate for Seoul to London is derived from the 8,861-km great-circle distance. Long-haul flights spend most of their duration at optimal cruise altitude (typically 35,000–40,000 feet), achieving effective speeds of 820–900 km/h. An additional 30–50 minutes accounts for taxi, takeoff, climb, descent, approach, and taxi at both ICN and LHR. Actual routing through controlled airspace may add 3–8% distance beyond the great-circle path due to air traffic corridors and restricted zones along the way.

Wind patterns and flight duration

Prevailing winds along the Seoul–London corridor have a moderate effect on flight time. Westbound flights may encounter mild headwinds from the general west-to-east upper atmospheric flow.

Practical travel context

This route links Asia and Europe, one of the busiest intercontinental corridors. Connections via Middle Eastern hubs (Dubai, Doha, Abu Dhabi) are common alternatives to direct flights. For stays shorter than 8 days, some travelers opt not to fully adjust to local time. Instead, they maintain a compromise schedule between origin and destination time, which can be effective for brief business trips.

Frequently asked questions: Seoul to London

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