A Postmaster Sank a Mailbox Underwater to Save His Town

Susami was dying. This fishing village of 3,700 people in Japan had become the kind of place tourists drove through without stopping.

Then Toshihiko Matsumoto, the 70-year-old postmaster, decided to do something that sounded completely impossible. He would sink a working mailbox into the bay and let divers send real mail from the bottom of the ocean.

"I thought it would be interesting if divers could send letters from under the sea," Matsumoto said. After 40 years working for the post office, he knew the system inside and out.

The logistics were tricky. Regular postcards dissolve underwater, so Matsumoto arranged for waterproof plastic postcards to be sold at the local dive shop for around $1.50. He provided oil-based markers that wouldn't smear underwater.

The bright red cast iron mailbox was anchored 10 meters below the surface of Susami Bay. It became an official branch of the Japanese postal system, meaning every letter sent from it would be delivered anywhere in the world.

The boxes rust in saltwater, so they're replaced every six months. Two boxes alternate, with one getting repainted while the other sits on the ocean floor.

The process is simple. Visitors buy a waterproof postcard, write their message, and dive down to drop it in the box. For beginners, the local dive shop offers guided lessons.

Every day, the dive shop manager collects whatever mail has accumulated and brings it to the post office for delivery.

The Ripple Effect

The underwater mailbox earned a Guinness World Record in 2002 for the deepest underwater post box. Today it receives between 1,000 and 1,500 pieces of mail daily.

More than 38,000 letters have been successfully delivered from the ocean floor. The mailbox even appeared in a major automobile commercial in 2015.

Matsumoto's hunch was right. Susami, which had nothing special to attract outsiders, now draws divers from across the globe. A struggling town found new life because one person asked a simple question: what if?

It's one of the most creative acts of small-town revival on record, dreamed up by a postmaster who just thought it would be interesting.