The beautiful island of Koh Mak is situated in the eastern gulf of Thailand close to the Cambodian border. It is the 3rd biggest island in that area after Koh Chang and Koh Kood. The island is a small tropical paradise covering an area of 16 square kilometers with it being around 10km wide and 5km from north to south. Koh Mak is privately owned by a small group of families who each strive to work together to ensure the island proceeds in a sustainable way by following the ideals of ecotourism. There are 24 resorts on Koh Mak which provide the perfect surrounding for relaxed holidays. On Koh Mak you will not find any jet-skis, nightclubs or red lights districts. Instead you can encounter biking trails, diving schools and laid back cafes amongst beautiful beaches with crystal clear water.
In addition to the beautiful beaches, the island's hinterland is very green with natural forest as well as coconut and rubber plantations. The majority of local people still work on the coconut and rubber farms which are the island’s main export products . Koh Mak provides a diversity in flora and fauna which can be discovered on land and under water in the near marine national park. Being a tropical island, you might have the chance so see scorpions, snakes, spiders and colorful butterflies. Unfortunately, there are jellyfish in the shallow water of Koh Mak’s coastline. Therefore most resorts installed nets in order to provide save swimming areas in the sea.
Koh Mak is located in the southeast of Thailand and has a tropical climate with warm temperatures throughout the year. There are two main seasons: the northeast monsoon season from December to April with dry, sunny and warm weather and the southwest monsoon season from mid-May to November with rainfalls. From June untill October most rain is falling, with 4,000mm in an average year. During this period many resorts and shops close, while others stay open and offer deeply discounted prices.
Koh Mak is located around 350km from Bangkok and 60km from the nearest regional centre Trat.
You can take a flight from Bangkok Suvarnabhumi airport (BKK) to Trat airport (TDX) with Bangkok Airways which offers three daily flights. From Trat it is best to take a taxi to the pier Laem Ngop. Alternatively you can take a bus from Bangkok to Trat or directly to the pier Laem Ngop. Bus rides take about 5 hours. Mini busses are generally a bit faster. Services from Bangkok run from Ekkamai station, Mo Chit station and from Suvarnabhumi airport and cost about 200 to 300 Bath.
There are buses, private cars and taxis running daily from Pattaya airport to Trat or directly to the Laem Ngop pier. Driving can take anywhere between around 3.5 and 5 hours. Buses generally cost around 300 Baht and a private car will cost between 2400 and 4500 Baht depending on the season and company you choose.
From the Ko Mak pier in Laem Ngop (Trat)
Seatales Speeboats , Panan Speedboats , Leelawadee Speedboats , and Suansuk Speedboat provide daily speedboat service to Koh Mak, with the last boat leaving for Koh Mak at 16:00. Seatales and Suansuk provide service to Ao Nid Main Pier, Panan provides service to the Ko Mak Resort pier on Ko Mak's north shore, and Leelawadee provides service to the Makathanee pier. Frequencies might be reduced in the off season. The price is 450 Baht per person one way.
10:30am Leelawadee; 11:30am Seatales; 12:30pm Suansuk; 1pm Panan; 2pm Leelawadee; 2:30pm Seatales; 3pm Suansuk; 4pm Panan.
From the Laem Sok pier (Trat)
CP Laem Sok group  provides daily service to Ko Mak's largest pier at Ao Nid, before continuing on to Ko Kut. There was also a once-daily catamaran service between Laem Sok and Ao Nid , which has now been postponed. Boonsiri High Speed Catamaran  or Koh Kood FantaseaCatamaran  . These two are the same, just different calling. (starting on 15 November 2013) 600 Baht per person one way or 1200 Baht per person incl. bus transfer from Bangkok. Pick up point in Bangkok is Khao Sarn Road and Shell Gas Station in Bang Na, at 7-8am. Sailing time between 50-60 Minutes. Departures at 2pm. daily from Laem Sok to Koh Mak(Ao Nid Pier) and Koh Kood(Bang Bao Beach), also during low season. free taxi from Trat to the pier in Laem Sok. Frequencies might be reduced in the off season.
From Ko Chang
During the high season there are a twice daily speedboat transfers from Kai Bae Hut Speedboat at 09:00 and 11:00 to the Makathanee pier on Ko Mak. First boat is a sure bet, the 2nd only if there are enough passengers. In the low season this service won't run. On the south end of Ko Chang you can catch either a speedboat or the slower wooden boat from Bang Bao Boat. Bang Bao boats arrive at the Koh Mak Resort Pier on Koh Mak. The slower wooden boat stops at Koh Wai on the way to Koh Mak.
From Ko Kut
There is 3 boat services. One is the once-daily catamaran boat service (Boonsiri High Speed Catamaran ) running from Bang Bao Beach at 11:30, arriving at Koh Mak(Ao Nid Pier) about 30 minutes later. The other two are Kai Bae Hut Speedboat and Bang Bao Boat, providing twice-daily speedboat service (KB huts speed boats ) from most resorts that own private piers. The Kai Bae boats leave at 09:30 and 12:00, arriving at Ko Mak Makathanee Pier about 45 minutes later. The Bang Bao boats arrive at Koh Mak Resort Pier. All of these boats typically continue to Ko Chang or the mainland after docking at Koh Mak.
Ko Mak has 27 km of coastline, many long sand beaches, a few hills and it is about 16 km² in area. For exploring the mostly flat island, bicycles are the best option and most beaches and restaurants are within easy walking distance. Along with the “Low Carbon Initiative Koh Mak” lovely bike paths through the laid back nature were created . Bicycles (for ladies and proper mountain bikes) can be rented at several locations on Koh Mak for about 100-250 Bath per day, e.g. at the Coco Bar, Island Huts and Ao Kao Resort near Ao Kao beach and at Koh Mak Resort near Ao Suan Yai beach . Scooters are available for 300-400 Baht per day at many resorts if you don’t want to bike but are not necessary when taking the size of it island into account. Taxi service is offered for transportation to any point of the island at a standard rate of 50THB per person one way. Exploring the surrounding of Koh Mak can be done in a Kayak, which can be rented at the resorts of the two main beaches Ao Kao Resort on Ao Kao and Koh Mak Resort on Ao Suan Yai. On low tide, it is possible to walk to Ko Kham (privately owned), which is a smaller island less than 1 km northwest of Ko Mak. Ko Phi, also north west from Ko Mak but southwest from Ko Kham, is not occupied and can be reached by kayak.
The islands’ main attractions are the beautiful beaches with crystal clear water and the national marine park as well as the natural forests and green hinterland. The largest beaches are Ao Kao beach located on the southwestern side of the island and Ao Suan Yai beach which faces the northwest, and both are around 5km long. The unusual cross form of Koh Mak leads to calm and warm ocean water in its bays. From the Vista Lookout Point beautiful views can be gathered of Koh Kham and 13 other islands to the North which are part of the Koh Chang National Marine park archipelago . The national marine park offers unspoiled coral riffs that can be explored by going snorkeling or taking a diving trip with one of the two diving schools 
Advanced Diving Courses: To increase your confidence and build your scuba skills, so you can become more comfortable in the water, the Advanced Open Water Diver course helps you get more dives under your belt while continuing to learn under the supervision of your PADI Instructor. And no, you don’t have to be “advanced” to take it – it’s designed so you can go straight into it after the PADI Open Water Diver course. The courses ranging from AWARE-Fish Identification to Underwater Photography and will introduce you to new activities and new ways to have fun scuba diving. Prices are around 3.500 Baht for a daytrip and 13.500 Baht for the 3-4 day open water divers license.
There are no chains like 7Eleven but several minimarkets all across the island are selling food supplies and basic toiletries. Don’t expect too big of a variety of goods, but generally speaking: all you need is available - including snacks, ice-cream, fresh fruits, cold drinks, beer, sunblock (and aftersun!), mosquito repellant, tooth paste ect. A few little shops selling self-made art and clothes can be found on the main road north of Makathanee pier. There is no ATM available on Koh Mak. This is due to the fact that no car ferry exists to the island and the inhabitants voted against the start of such a service. Hence no bank will put an ATM on the island. Therefore you should bring enough cash for your stay. In worst case, you can get cash at some resorts against a credit card charge of 2-5%. Some shops such as the diving schools and most resorts accept credit cards against a 3% surcharge 
There is a wide range of food options available for the the size of the island.
You will not find any nightclubs on the island. There are however a few bars where you can enjoy a sunset cocktail.
There are 24 spacious resorts on the island where you can relax and have enough space to find your private oasis. Almost all resorts have direct sea access and there is a good chance to see and hear the ocean from your bungalow/room. Prices are fair for the paradise you can expect. For high season (November - February) it is recommended to book ahead, especially for weekends. Although there are many different places to stay, most of them can easily be fully booked during Thai holidays that Western tourists are usually unaware of. While some of the resorts close in the off-season (June-October), others offer significant discounts for everybody who is not disappointed by some rainfall.
Thanks to an optical fiber connection internet speed is very high on the island. Thai sim cards provide reliable service but should be bought on the mainland. You might experience occasional short interruptions of electricity during thunderstorms in rain season which is usually restored within minutes.
There are daily speedboats from Koh Mak to the Laem Ngop on the mainland, and to Koh Chang and Koh Kut. Bang Bao Boat has one slow wooden boat to Koh Chang each day, and there is a daily Boonsiri catamaran to the Laem Sok on the mainland. The Seatales , Boonsiri, and Suansuk depart from Ao Nid main Pier; Panna boats depart from Koh Mak Resort Pier; Leelawadee boats depart from the Makathanee Pier. - Frequencies might be reduced in the off season.