“Submarine Mailbox” is a mailbox installed on the seafloor, also called “Mailbox in the sea”, and can be seen in Japan in Wakayama Prefecture Susami Town, Shizuoka Prefecture Izu City, Okinawa Prefecture Naha City etc. As part of the event in 1999, it was the start of being established by the director of Wakayama Prefecture Susami Post Office. The place of installation is 100 meters from the shore of the Karekinada coast of Susami Town in Wakayama Prefecture, located at the bottom of the water at 10 meters depth.
The visited diver posts it at the “Submarine Mailbox” set at the diving spot, and the postcard collected from the sea is shipped to the whole world from the Susami post office. An average of 10 postcards are posted a day on average, and around 50 or so on a weekend or summer vacation are posted. In 2002, it was certified as Guinness Book and posted as ‘Mailbox in the deepest place in the world’. “Submarine Mailbox” got very popular and in 2011 the number of postings exceeded 30,000. Even diving beginners will be able to post by themselves if they participate in experiential diving, you can also ask staff for posting.(200 yen, air mail available)
However, because it is in the sea, post deterioration is intense, it may be that it is not the original color red with barnacles and seaweed attached after several months of submersion in the sea. It seems that now they are replacing two posts several times a year. They are sticking to the old round post and they seem to be recovering and using round posts that are no longer used by municipalities nationwide. However, it seems that posts of such forms are hard to gather at the moment and are struggling.
There is the submarine mailbox under bottom of the sea, where approximately 100 meters from the shore of Susami town, Wakayama, at the depth of 10 meters below the surface of the sea. It was certified as “the mailbox in the world’s lowest place” in 2002 by Guinness Book of World Records.

You can confirm it on a map of the lower part of this page, and it is surely underwater.
The submarine mailbox was put into this place by a suggestion of the director at local post office as part of the event in 1999. After the event was over, it is used in the same way as a common mailbox.

A letter, which the diver who visit this place posts in “the underwater mailbox”, is collected and sent from the Susami post office to the world, (You can use air mail.)

The posts are changed once a year. It seems that they use two posts one after the other every year.
In 2015, it appears in a TV commercial of the car.

Information
Name: | Submarine Post |
Adresse: | Susami 4857-74 Nishimurogun Susamicho, Wakayama 649-2621 Japan |
Access: | JR Kisei-honsen Line “Susami-eki Station” (23 minutes walk) Courtesy bus service is available for the guest of club-noah, reservation required. |
Tel: | (+81)739-55-4511 |
Price/Charge: | 200 yen (The price of postcard for “Submarine Post” only) Please refer the official web page. |
Official site: | http://www.susami.club-noah.net/ |