Phuket runs on Indochina Time (ICT), UTC+7, year-round — Thailand does not observe daylight saving time, so the offset from home never shifts partway through your trip.
Common offsets travellers ask about
Roughly 12-13 hours ahead of US East Coast time (varying with US daylight saving), 6-7 hours ahead of UK time (similarly varying), and 1-3 hours behind most of Australia depending on the state and season — always worth double-checking against a live time converter rather than memorising a fixed gap, since the US and UK ends of that comparison do shift twice a year even though Thailand doesn't.
Managing the adjustment
- For long-haul flights from Europe or North America, expect several days of genuine adjustment — morning light exposure and avoiding long naps in the first few days both help reset faster
- Booking a lighter first day or two on arrival, rather than an immediate full itinerary, makes the adjustment considerably less miserable
- Melatonin and other sleep aids work for some travellers adjusting across this many time zones — check what's legal to bring into Thailand before packing any, since rules vary by substance and quantity
Coming home
The adjustment back is often harder than arriving, particularly travelling east across many zones — building in a buffer day before returning to work is a reasonable piece of trip planning most people skip.