Japan's Deepest Underwater Post Box

In Japan's Susami Bay, an extraordinary postal service lies 10 meters (approximately 33 feet) beneath the ocean's surface, offering a unique way to send mail. This submerged post box allows adventurous individuals to combine a dive experience with the simple pleasure of sending a postcard. It's a testament to human ingenuity and a popular attraction for both local and international visitors seeking an unforgettable way to communicate.

The idea for this distinctive underwater post box originated in 1999, conceived by Toshihiko Matsumoto, who was then the 70-year-old postmaster of Susami. His vision was to create a novel attraction that would draw tourists and divers to the small fishing town. The initiative proved successful, and in 2002, the Susami Bay post box was officially recognized by Guinness World Records as the world's deepest underwater post box, significantly boosting the town's profile.

To send a message from this aquatic mail collection point, divers first purchase special waterproof postcards and use oil-based markers to ensure their messages remain legible underwater. After writing their greetings, they descend to the red mailbox to deposit their mail. A local dive shop employee regularly collects the postcards, which are then taken to the surface and onward to the conventional postal system for delivery. While the Susami Bay post box was indeed once the deepest, a new record was set in 2015 by a post box in Malaysia, located at a depth of 40 meters. Nevertheless, the Susami Bay underwater post box continues to be a fascinating and beloved landmark, typically receiving between 1,000 and 1,500 pieces of mail annually.