Which island nation is the only one that shares a border with another country?

There are many island nations which share borders with each other.

- The United Kingdom and the Republic of Ireland are both island nations and share a border with each other on the island of Ireland.

- Haiti and the Dominican Republic are both island nations and share a border with each other on the island of Hispaniola.

- Indonesia and Brunei are both island nations and share a border with Malaysia on the island of Borneo. Malaysia is not an island nation.

- Indonesia and Timor Leste are both island nations and share a border with each other on the island of Timor.

- Indonesia and Papua New Guinea are both island nations and share a border with each other on the island of New Guinea.