The district was established in December 1901.

The origin of the name is unclear, but it may originate from the Javanese word lantas, meaning a type of grill for fish. The name of the island was officially changed to "Koh Lanta" in 1917.

From archaeological discoveries, it is believed that the area was one of the oldest communities in Thailand dating back to the prehistoric period. It is believed that this province may have taken its name after the meaning of Krabi, which means sword. This may have stemmed from a legend that an ancient sword was unearthed prior to the city’s founding.

The district,located approximately 70km from Krabi Town, consists of two major islands, the larger, more populated Koh Lanta Yai (Commonly known as simply Koh Lanta) and the smaller Ko Lanta Noi, as well as several minor islands. The island (Koh Lanta Yai) has 9 attractive white sandy beaches, splendid scenery; coastlines have more than 70 small islands and plenty with forest, coral reefs and under water life. The geography of the island is typically mangroves; coral rimmed beaches; and rugged tree covered hills. A popular tourist destination, the islands are known for their long, sandy beaches and scuba diving.

Neighboring districts are Nuea Khlong  to the northwest and Khlong Thom to the northeast and east. Whereas, the rest of the sides are surrounded by Andaman Sea.

134 km² of the district belong to the Koh Lanta National Park , which was established in 1990 as the 62nd national park of Thailand.

Tourism on Koh Lanta, like the rest of Krabi province, has exploded only very recently. In the early 1990s only the most adventurous travelers visited the island, staying in only the most basic accommodation costing the likes of 50-100baht a night. Nowadays, however, the place has turned into one of the major destinations for visitors to Krabi. The development however, is still nothing on a par with the likes of Phuket or Koh Samui.

Attractions

• Koh Lanta National Park Covering a total area of 152 square kilometres, Mu Koh Lanta National Park is located in Amphoe Koh Lanta and consists of many islands. The two major islands are Koh Lanta Yai and Koh Lanta Noi 

• Lanta Old Town It's one of the region’s most culturally diverse with Chinese merchants, original Thai fishing families and an ancient Sea Gypsy community. Many years ago, Koh Lanta's Old Town acted as the port and commercial center for the island and provided a safe harbor for Arabic and Chinese trading vessels sailing between the larger ports of Phuket, Penang and Singapore.

• Khao Mai Kaew Caves These Caves, located in the centre of the island, house impressive stalactites and stalagmites, some of the caves are just very large and one contains a pool.

• Sea-Gypsy Village Known to the Thais as Chao-Le, sea gypsies have occupied the area for hundreds of years settling along the coast in stilt-built houses erected in the sea. They are unique in that they mix very little with the general population, speak their language and have their very own supernatural and traditional beliefs and rituals.

• Orchid Nursery Farm This farm is for those who like flowers. The Orchid Nursery Farm is located at Long Beach (Pra Ae beach).

Activities

Diving & Snorkeling

The diving sites surrounding Koh Lanta are considered by many to be among some of the best the country has to offer. There is an enormous variety of fringing reefs, marine life, caves, rocks and islets.

Hin Daeng and Hin Muang  near Koh Lanta are perhaps the best dive sites in Thailand (ranking in the world’s top ten) with more than 200 hard corals and 108 reef fish catalogued in a study underway, but thousands more organisms abound. Hin Daeng has the steepest and deepest in the whole of the country with beautiful marine life. Hin Muang next door is completely underwater and it is covered with delicate violet coral. The sites also have one of the world's highest incidences of whale shark sightings.

Fishing

Fishers usually catch the likes of marlin, sailfish barracuda, red snapper and tuna during a long tail boat trip having a choice of either day fishing or night fishing.

Kayaking

The east side of Koh Lanta with its rich mangroves is the most suitable for kayaking in peace and quiet while admiring the natural surroundings. Kayaking is also the best way to explore caves. Kayaking can also be done in mangrove swam at Baan Tungyeepeng and Koh Talabaeng, the limestone cliff near Koh Lanta.

Trekking

Koh Lanta’s pristine forests with excellent flora and fauna are suitable for trekking. Elephant riding are usually arranged to take visitors to the top of the hill in Koh Lanta National Park.

Thai Boxing

There is one small boxing stadium on the island which hosts regular fights. The stadium is a popular place with foreigners for learning the art.

Koh Lanta now has its very own mini-boxing stadium which arranges regular fights. These are popular with foreigners interested in this ancient martial art. Tourists can train there if they wish as there is also a training camp.

Thai Cooking

Thai cooking courses on Ko Lanta offer foreign tourists the chance to learn to cook up all their favourite dishes such as tom yum kung, sweet green curry and chicken with cashew nuts.

Spa

Traditional Thai massage, characterized by its holistic approach to health, is aimed at enhancing not only one’s physical and emotional state but also to allow one to grow spiritually. There are many spa places on this island. However, massage on the beach is also possible – you won’t know however, if she is well-trained (otherwise there could be risks involved).