The Party Ko Phangan 
 Phangan, a short ferry ride north of Samui, might be the only destination where high season comes once a month. The local tourist calendar is tied to a lunar cycle that peaks during the Full Moon Party, an all-night rave fueled by cheap booze and designer drugs with thousands of people dancing on the sand of Hat Rin Nok (Sunrise Beach).

In the interval between parties, the entire island seems subdued and hungover, with shuttered beachfront bars, deserted cybercafes, and largely empty clusters of bungalows. If you aren't up for the 20-something rave scene, anytime other than during the full moon is when you want to visit Phangan. It almost feels like you have the island to yourself before and after each monthly bash, the only hints of which are empty bottles littering the beach. But soon enough, a few days before the moon waxes full again, the next batch of partyers arrives, fails to find a room, camps out on the beach, and the fun begins all over again.

The operation that started it all, Paradise Bungalows, is Full Moon Party central. Its bungalows, though utterly basic, are picturesque, climbing up the hillside or right on the beach under the shade of coconut palms. Standing head and shoulders above the Paradise Bungalows--literally and figuratively, as they're propped up on stilts--are the spacious cottages of Sun Cliff, well removed from the hubbub of the town near Hat Rin Nai (Sunset Beach). While some cottages have air-conditioning, the favorite has to be fan-cooled bungalow D2, a fabulous Swiss Family Robinson-goes-to-Asia "tree house," where the front end is 25 feet above the ground. The back wall is anchored to the rock of the steep cliff, and in a few spots the boulders intrude into the wood-ceiling bedroom. Even the bathroom has a tree growing up through the middle of the floor and out through the translucent corrugated-plastic roofing. French doors fold back to open two entire walls of the bedroom onto a wraparound balcony, and there's a hammock overlooking the sea.

Sunrise Beach is connected to Sunset Beach by a road lined with Internet cafes, bakeries, noodle shops, and souvenir stands. The main intersection, inexplicably dubbed Chicken Corner, is the island's commercial hub. You'll find the best dinner on the island just down a side street from this crossroads at the Old Lamp, a backpacker joint where shoes come off at the door, everyone sits on the floor, and the portions of curries and rice are massive.

The Secret West Railay Beach, Krabi 
 West Railay Beach looks and feels like what many tourists expect of the Thai islands: craggy karst cliffs and gorgeous beaches, reachable by a 20-minute boat ride, and, to get onshore, a wade through the surf with your bags overhead. The irony is that Railay is not an island at all; it's on the mainland, near the river town of Krabi. But when a spot is this isolated and undeveloped, with only four bungalow operations carved out of the thick seaside jungle, who cares that it's not surrounded by water?

Railay is carefree and casual. Resort staffs take over sections of the beach for pickup soccer matches around sunset. Although the concentrated cluster of bungalows brings longtail boats roaring in and out of the heart of the beach all day, it's not too difficult to find a peaceful stretch of sand. From a position on the beach facing out to sea, turn right and walk a couple hundred feet to the end, then wade out around the little headland. The beach beyond is nearly abandoned.

There's precious little difference between the four bungalow resorts at Railay; each consists of modern cottages lining a garden-like cement walkway running back from the beachfront. Railay Village Resort gets top marks if only because it tends to be the cheapest of the lot. The resorts are also the only games in town for meals (though there is a mini-mart/cybercafe where you can buy snacks). One drawback to Railay's being so far out in the boondocks is that prices for everything from lodging to bottled water are double or triple what you find on the islands. Don't let that discourage you from coming here. Even with the rates jacked up, things still seem inexpensive to most international travelers.

The Retreat Ko Lanta 
 A crowd of sign-waving Thai islanders standing three-deep greets ferries as they arrive in Lanta. It looks like a very confused protest rally, but each sign represents a different resort on the island. There's no public transportation on Lanta, so any hotel with vacancies sends an envoy to collect as many tourists as he can cram into the back of a miniature pickup truck. This may seem chaotic, but it works with surprising efficiency. And it's well worth putting up with to spend a few days on the most laid-back of the major ko.

 The west coast of Lanta is lined with an almost continuous string of bungalow resorts. Even so, it doesn't feel overdeveloped. The unbroken line of palm trees provides shade for wide, soft-sand beaches, and the single dirt access road that snakes down the island is sufficiently rutted and bumpy to give you the feeling you're way out in the sticks.

Relax Bay is aptly named. Set back from a private beach amid lush gardens, the solid, wooden bungalows have fan-cooled rattan interiors, floors made of dark wooden slats, and colorful hammocks strung on every front porch. A bridge arches like a cat's back over a stream flowing through the property. The dining area is open on all sides, and a breeze gently ruffles the curtains around the massage mats set near the beach. In addition to the wooden tables and chairs on the beach, there's an old canopy bed out on the sand for lazing away the afternoon. Nightlife revolves around a campfire by the water.

Just a few hundred feet up the beach from Relax Bay is the cheaper, funkier Lanta Marina Resort, a hodgepodge of cottages and bungalows run by a friendly woman named Nita. Her best bungalows--arranged around a U-shaped boardwalk--are built with loosely stacked branches. The wide gaps between them fill the rooms with a luminous play of light shafts on the gauzy mosquito netting around the beds. Nita describes it as traditional Thai construction and a primitive form of air-conditioning.

There's little to "do" on Lanta other than rest, sip fruity drinks, endure endless massages, and wander the beach admiring the swirling patterns left by miniature sand crabs.