Remember the last time you were diving underwater and you suddenly remembered an important letter you had to post that very instant? Yup, it has happened to all of us. Fortunately, these five places has us covered.

The underwater post office off the coast of Hideaway Island in the island nation of Vanuatu is one of the most famous in the world. It was established in 2003 and is located in 3 meters of water. The post office provides special waterproof postcards that tourists can drop into the submerged post box with their own hands, or ask the staff to do so.