With an area of just under 230 sq km and Thailand's third largest island, Ko Samui is a pretty big place, but most of the action and settlements of note predictably cling to the shoreline. Activity, noise and mayhem centres on Chaweng in the east, but gradually dissipates the further away you travel; however, the east and north coasts see far more visitors than the west coast and south coasts. The central part of the island, making up the bulk of its area, is unspoiled jungle.
Hat Chaweng is Ko Samui's tourist heart: a throbbing, pulsing maelstrom of elbows, traffic, noisy vendors, live music bars, cabaret acts and endless pharmacies, but the beach is pleasant.
Hat Lamai & the Southeast
More pleasant than its noisier neighbour (Chaweng), Hat Lamai's beach and lively village atmosphere make for enjoyable exploration. You're close enough to the action, while feeling removed as well. Intriguing small villages, waterfalls and hiking possibilities nearby.
Bo Phut & the Northeast
The coastal area of Bo Phut on the north shore is home to a few famous temples and Fisherman's Village, which makes for a fun and absorbing half-day's exploration, with many superb restaurants to boot.
Mae Nam & the North Coast
Things gradually gets quieter as you head west beyond Bo Phut. Restaurant and accommodation options thin out, but there's a beguiling sense of remoteness, plus treks off into the verdant hills.
Na Thon & the West
Little-visited outside the main settlement of Na Thon, the west coast offers awesome sunsets and the chance to escape the east-coast crowds. Na Thon itself has some decent restaurants and shops and a fine Chinese temple.