The World’s Deepest Postbox

April 16, 2024

Mailing a letter from this spot takes a bit of planning. It’s the world’s deepest postbox, and it’s located off the southeastern coast of Japan at a depth of 33 feet (10 meters). It’s recognized as an official collection point of the postal system and receives 1,000 to 1,500 pieces of mail a year.

The deep postbox is located near a fishing town called Susami that has a population of 5,000 people. Not everyone can jump in the water and mail a letter, however. It’s used by divers who get postcards from a local shop. They’re water-resistant, and the divers write their message using a paint marker.

When the divers submerge, they can place their cards in the postbox on the ocean floor. A worker from the same shop where the postcards are sold collects them every couple of days and then drops them at the post office in the town for delivery. The postbox is rotated every six months to allow for cleaning and repair due to corrosion by the seawater. It is replaced by the one spare postbox the shop has on hand.

The postbox came about because of action by the postmaster of the town in 1999. The town didn’t have an attraction for a fair that promoted the Kumano Kodo pilgrimage trail, so he proposed putting a postbox underwater to act as a tourist draw. An old postbox was used and installed just off the coast. It became the deepest postbox in the world. Thirty-two thousand pieces of mail have been deposited in the postbox since it was first installed.

About the author 

Daniel Ganninger - The writer, editor, and chief lackey of Knowledge Stew, the author of the Knowledge Stew line of trivia books, and editor of Fact World and the Knowledge Stew sister site on Medium, our ad-free subscription sites. I hope you learn many new things here that add to your knowledge.

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