Although Koh Kood (also spelled as Koh Kut) is the fourth island in size (25km x 12km) it remains less developed and less visited by mass tourism. The island is approximately 315 km east from Bangkok and 80 km offshore. The island is in Trat province and can be reached from Trat city. The ferries will leave from the Laem Sook pier (also spelled as Leam Sok) It is also possible to reach Koh Kood by ferry from Koh Chang island and the small island Koh Mak. Both are located north west of Koh Kood.
Ko Kood is as much a nature lover’s destination as a beach lover’s paradise. Parts of the island are still covered with virgin tropical rain-forest while other parts are covered with palm groves and rubber plantations. The island is quite with only small scale nightlife, no go-go bars, only 3 ATMs, only one small bank and not a single 7-eleven supermarket. But there are a few luxury beach resorts. Main centre of tourism activities is Klong Chao beach between Away Koh Kood and the Tinklebel resort. Here you find some small scale bars and restaurants, diving schools and a ATM’s. The other resorts on the island are mostly tucked away from the main road and quite isolated. This island is the most eastern one and the closest to the border with Cambodia. From Trat city it is also possible to travel into Cambodia over land. By doing so you avoid the busy border crossing Aranyaprathet – Poipet which is further north. Sihanoukville is a popular coastal destination in Cambodia.
The drive from Bangkok to the Leam Sok Pier will take 5 to 6 hours by minivan or bus. After that you need to take a ferry boat which also takes around 1 to 2 hours. It is possible to go to Trat bus stration by public bus from Bangkok (Mo Chit and Ekkamai) or from Pattaya. From the bus station you can take a Songtaw (shared taxi) to the assemblie point of one of the ferry companies. Another option offered by one of the ferry companies (Boonsiri) is a cobination ticket of bus ride and ferry crossing. A private bus picks you up near the Khaosan Road in Bangkok and brings you directly to Boonsiri assembly point near the pier. Ferries usually only operate at daylight hours and want to avoid the nightfall. This means that the majority will depart before 13:00 PM. If you arrive in the late afternoon or early evening you have to spend a night in Trat city. If you want to make the journey in the same day, you have to catch the bus in Bangkok between 5 and 6 o’clock in the morning. All together it takes some effort to reach this island. This is probably what keeps Ko Kut untouched and unspoiled.
Background info on Wikipedia