What to know before you KO 
 Getting to the islands: There's no need to book flights within Thailand ahead of time. Travel agencies litter the Bangkok backpacker enclave of Khao San Road and its parallel, Rambuttri, where you can pick up Bangkok Airways tickets--B.A. is cheaper and nicer than Thai Airways--to Samui ($90 one way) for the gulf islands or to Krabi or Phuket (each about $65 one way) for Railay, Phi Phi, and Lanta, on the Andaman Sea. Be ready to pay $2 to $10 in local currency for arrival and departure taxes at every airport. Buses and trains from Bangkok are cheaper but eat up at least 12 hours; plane trips are 90 minutes max.

Island-hopping: Navigating between the islands is easy. Ferries ply the waters between popular isles several times daily for $5 to $10, and travel agents display routes and departure times. Short hauls that lack ferries are served by longtail boats--speedy, huge canoes with oversize motors roaring at the back--for $1 to $4. Flights between Samui and Krabi cost under $50. To get around the larger islands, songthaews (pickups and vans that act as public buses), tuk-tuks (three-wheel taxis), or scooter taxis cost a few bucks on any run. If you book a hotel in advance, they'll often pick you up at the airport or ferry dock.

Communicating: English is widely spoken, though starting conversations with a greeting of sawat-dee and ending with a khowp khun (thank you) is always appreciated.

 Lodging: It may seem crowded--especially during high season, November through April--but don't panic. With rare exceptions, supply exceeds demand, and you can almost always find a room. Calling ahead ensures a better selection, however, so if your heart is set on that beachside bungalow, book a few days in advance. Air-conditioned rooms cost more than fan-cooled ones, but many people actually prefer fan rooms with mosquito netting on the beds. It's more relaxing when you can throw open the windows to tropical breezes and sounds of gentle surf rather than being in a sterile, musty room with A/C.

Ko Samui   Lodging The Island Chaweng Beach, 011-66/77-230-751, rft.co.th, $25--$35 with fan, $35--$83 with A/C

Food Budsaba Restaurant Muang Kulay-pan Hotel, Chaweng Beach, 011-66/77-422-305

Activities Sea Safari Thailand 011-66/77-230-567, $45 all-day boat tour of Ang Thong Marine Park (snorkeling, sea kayaking, elephant ride)

Ko Phi Phi 
 Lodging PP Charlie Beach Resort Lo Dalum Bay, 011-66/75-620-595, ppcharlie.com, $30--$70 with A/C

Maprao Hat Yao, 011-66/75-622-486, maprao.com, $8.75--$25 with fan 
  Food Le Grand Bleu Ton Sai Bay, 011-66/1-893-5096

Jungle Bar Phi Phi Island Cabana Hotel, Lo Dalum Bay, no phone

Ko Phangan 
 Lodging Sun Cliff Hat Rin Nai, 011-66/77-375-134, $6.25--$18 with fan, $28--$35 with A/C

Paradise Bungalows Hat Rin Nok, 011-66/77-375-244, $5--$10 with fan

Food The Old Lamp Hat Rin Nok (south of Chicken Corner), no phone

West Railay Beach 
 Lodging Railay Village Resort Ao-Nang, 011-66/75-622-578, railayvillage@hotmail.com, $13--$20 with fan, $30--$63 with A/C

Ko Lanta 
 Lodging Relax Bay Phra-ae, 011-66/75-684-194, relaxbay.com, $18--$75 with fan, $33-- $45 with A/C

Lanta Marina Resort Phra-ae, no phone, kolanta.net, $2--$23 with fan