Zadetkyi
Zadetkyi Island or Zadetkyi Kyun, also known as Saint Matthew's Island, is an island at the southern end of the Mergui Archipelago, Burma. Its northern side forms the southern shore of Hastings Harbor, where there is a base of the Myanmar Navy.

Geography
Having a length of about  and an area of , Zadetkyi is the largest island of the southern group of the archipelago. It has two prominent peaks, the highest of which is 864 m and is located near the middle of the island, at its southern end rises a  high summit. The island is hilly and densely wooded and lies  south of Hastings Island.

Nearby islands
The Alladin Islands, the largest of which is Than Kyun, are a scattered cluster of islands extending to the W and SSW of Zadetkyi Island.

References 

Mergui Archipelago
Tanintharyi Region