A unique post box was found at the depth of 10 meters off the coast of Susami Bay. It was first installed in April 1999. Toshihiko Matsumoto, the then-postmaster of the village, came up with the idea to encourage divers to visit the sleepy towns.

The divers followed his idea. Some 1,000 to 1,500 pieces of mail are sent through the underwater post box each year, totaling 38,000 since it was set up.

The red underwater post box is not the only unique post box in Japan. In fact, they’ve got hundreds, maybe thousands, of them spread across the country. Each one with a design that reflects the culture and history of their locations. Kawaii!

This post box mainly lures those people who purchase water-proof cards on which the message is written with the help of the oil-based paint markers so that it can remain intact on the card despite the underwater immersion. People then dive into the sea to post their mail.  

In the year 2002, the Guinness Book of World Records recognised this 10-meters-deep, underwater, red post box in Susami Bay, Japan within which approximately 32,000 pieces of mail have been posted till date.