Jet lag plan
London is 9 hours behind Sydney. You're traveling west — the easier direction. Your body delays its clock.
About 16,994 km northwest · approximately 20.5-hour non-stop flight · an ultra-long-haul flight.
The route from Sydney, Australia to London, United Kingdom covers roughly 16,994 kilometres in a northwest direction. At standard jet cruise speed plus a one-hour allowance for taxi, climb, and descent, a non-stop flight takes about 20.5 hours. This route crosses the equator. The destination's season is reversed relative to the origin, which can amplify the perceived disorientation of jet lag — your body lands not just in a different clock but in a different daylight regime.
Sydney is in the subtropics. Day length varies by roughly two hours between summer and winter; light remains a reliable circadian cue most of the year. London is in the temperate zone. Day length varies by four to six hours between summer and winter, so the season of your trip materially affects available morning and evening light.
With a 9-hour offset, the standard 09:00–18:00 working days in Sydney and London do not overlap. Live collaboration on this route requires at least one side to take an early or late call. The least costly compromise is usually an early-morning call in London and a late-evening call in Sydney.
Both cities observe daylight saving time. The hour offset on this route can shift by one hour twice a year (typically March and October/November), and the two clocks rarely change on the exact same date — expect a transient 1-hour mismatch for two to three weeks per transition.
If you are a lark (morning type): Westward travel is the easier direction and larks usually feel close to baseline within 5 days. The risk for larks is overshooting: stay up later than you feel like at the destination for the first two nights to avoid waking before local sunrise.
If you are a night owl (evening type): Westward travel suits owls because the body prefers delaying over advancing. A 9-hour westward shift typically clears in 5 days. Stay outside in the evening light at the destination and avoid early-morning bright light for the first three days.
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The great-circle distance from Sydney to London is about 16,994 kilometres. A typical non-stop flight takes around 20.5 hours at standard cruise speed; routes with connections add two to four hours.
London is currently 9 hours behind Sydney. Both cities observe daylight saving time. The hour offset on this route can shift by one hour twice a year (typically March and October/November), and the two clocks rarely change on the exact same date — expect a transient 1-hour mismatch for two to three weeks per transition.
Westward travel — which this route is — is the easier direction. Your body delays its clock, which is closer to its natural tendency. Most travellers clear a 9-hour westward shift in 6 days.
For a 9-hour shift, 0.3 to 0.5 mg of melatonin taken three to five hours before target bedtime at the destination is the dose supported by the Cochrane review. Higher doses (3–5 mg) do not advance phase better and increase morning grogginess. Start one day before departure.
Yes — for shifts of four hours or more, shifting bedtime and wake time by one hour per day, starting three days before departure, materially reduces post-arrival jet lag.
Owls (evening types) recover faster on westward routes because the body prefers delaying over advancing. Larks may overshoot — they should stay up later than they feel like at the destination for the first two nights.