How the coast works
Almost every beach people come to Phuket for sits on the west coast — facing the Andaman Sea and getting the sunset. The east side is taken up by ports, mangroves and marinas: there is nowhere to swim there, which is worth knowing before you pick a hotel off a map.
The western strip runs roughly fifty kilometres north to south, and its two ends have little in common. The south means compact bays, a cafe every twenty metres and the highest density of people. The north means kilometre-long stretches of sand, hotels hidden behind trees and almost nothing else. The middle is the compromise.
The second factor is season. From May to October the southwest monsoon drives swell onto exactly this coast, and some beaches go from calm to unswimmable. Flags and rip currents get their own article, but the general rule is simple: the more exposed the beach, the rougher it gets.
The south: bays where everything is close
Patong. The island's main beach and its most maligned. Three kilometres of sand, an even shallow entry, loungers, parasailing, jet skis and Bangla Road two hundred metres away. By day it is perfectly decent; by night it becomes the loudest district in Thailand after Pattaya. Ideal if you want everything within walking distance and have no plans to sleep before midnight.
Karon. Next door to Patong, longer and noticeably calmer. The sand squeaks underfoot thanks to its coarse grain — a local point of pride. One significant drawback: the bottom drops away sharply and in swell season a strong backwash forms at the shoreline. Not a beach for small children.
Kata. The most balanced beach in the south: a short bay, a decent entry, cafes and shops nearby, but none of the party atmosphere. In summer it hosts surf lessons; in winter it is a quiet family spot. Kata Noi over the headland is smaller, pricier and quieter.
Nai Harn. The far south, a bay ringed by hills, a freshwater lagoon behind the sand and very little construction. The enclosed shape softens the swell compared with its neighbours. There are few cafes and everything closes early — a plus or a minus depending on why you came.
Middle and north: space instead of facilities
Kamala. Quiet, elongated, with a local village rather than a hotel strip. A good choice for a steady holiday with no nightlife but working shops and a market.
Surin. Small, handsome, ringed by expensive hotels. The water entry is good, though swell season brings a strong backwash. There are almost no facilities on the sand itself — they were cleared out some years ago.
Bang Tao. Nine kilometres of sand, the longest stretch on the island. The northern end holds the Laguna luxury complexes, the southern end the beach clubs. Between them are empty sections where you can walk twenty minutes without meeting anyone.
Nai Yang and Mai Khao. The far north, beside the airport. Mai Khao is eleven kilometres of near-wild beach where landing aircraft pass low over the water and turtles come ashore in season. It is shallow, the tide retreats tens of metres, and the nearest shop may be a couple of kilometres away. A place for silence rather than convenience.
Freedom Beach. A small bay between Patong and Kata, reached by longtail or a steep path. The water is visibly cleaner than its neighbours precisely because no road reaches it. There is an entry fee and the loungers are expensive, but the view earns it.
Choosing for yourself
With small children: Kata, Nai Yang, Mai Khao — gentle entries and softer waves. Emphatically not Karon or Surin during the rainy season.
For nightlife and everything on your doorstep: Patong, with no real alternative. For quiet and nature: Mai Khao, Nai Harn, Nai Thon. For balance: Kata and Kamala.
One practical note: the beach you sleep on is not the only beach you will see. South to north is an hour to ninety minutes by car, so it makes more sense to pick a convenient base and cover the rest in a day. A sightseeing tour handles that entirely, viewpoints included — and not everyone enjoys driving those mountain roads themselves.