Mataking Island, the subject of a souvenir sheet issued by Malaysia on November 17, 2015 in Part
III of the “Islands and Beaches” series, was the site of Malaysia's first underwater mailbox.

Malaysia has hosted four underwater mailboxes. The most accessible ones are at Redang Island, Terengganu and Mensirip Island, Johor. The latter has the distinction of being a "royal" mailbox installed as part of the 2016 Kembara Jelajah Pulau Mersing (Mersing Island Adventure Tour) project promoting postal tourism and nature conservation, led by the Sultan of Johor, HRH Sultan Ibrahim.

A more remote one is located off Mataking Island, a resort that was the subject of a souvenir sheet issued by Malaysia on November 17, 2015 as Part III of the “Islands and Beaches” series. This underwater mailbox, Malaysia’s first, was mounted at the front of the wheelhouse of the wreck of the 40-foot cargo ship Mataking I that was sunk in 2006 to form an artificial reef at the dive resort. The mail is placed in water proof plastic bags before it is deposited in the mail box at a depth of 20 metres under the surface. The mail is collected twice a week and receives a commemorative handstamp before being placed in the mail system.

The shallow reef atoll of Pulau Layang-Layang in the Spratly Islands north of the island of Borneo is the site of another of Malaysia’s more remote underwater postal installations. This mail box is more significant because Malaysia’s ownership of the island is disputed by China, Taiwan and Vietnam. Malaysia has had a military presence on the island since the early 1980’s. In 1991 a diving resort was completed and in 2004 a marine research station was established. In 2015 a Malaysian poskod (post code) was granted and the code 88005 can be seen displayed on its underwater post office box. The first two digits indicate the state of Sabah. At a depth of 40 meters below sea level, this post office box made its way into the Malaysian Book of Records for establishing a world record for the deepest mail box. Waterproofed mail received a special postmark, and was stamped with the Malaysia Book of Records logo. According to the resort management, operations at the resort in Layang-Layang were suspended in 2023 on instructions from the government indicating that infrastructure work was needed “to ensure the safety of all visitors and the resort's readiness to carry out operations.” The correspondence pointed out, “Layang Layang Island / Pulau Layang Layang (PLL) is located in the Security Zone of Malaysia, hence it is under the full jurisdiction of the Government.” Although it may not be currently active, Layang-Layand continues to claim the record as the world’s deepest mailbox.