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Blog > Postcards from under the sea

We’ve written before about the Underwater Postoffice in Vanuatu, and we thought at the time it was the only place you could post a letter underwater in the world.

Well, turns out that isn’t quite true! Postcrosser Cindy (aka cindybeaule) let us know about an underwater post box in Susami, Japan, which was put in place in 1999 as part of a fair to promote the Kumano Kodo pilgrimage trail. It’s a collaboration between the former postmaster, a man called Toshihiko Matsumoto, and the local diving community. Waterproof postcards are sold in the dive shop, and you have to write your message using waterproof oil-based markers, so the message won’t wash off.

You need diving gear to even reach the post box, because it’s 10 metres below the surface. It’s actually in the Guinness Book of World Records because it’s the deepest post box in the world, and they have a certificate to prove it! The boxes are made of cast-iron, so there are actually two used in rotation, so they can be cleaned and repainted.

I even did some more poking around, and it turns out there are a few other underwater post boxes. There’s one in the Malaysian island of Mataking, another one in the Jemeluk Bay Underwater Gallery in Indonesia, and two “dry” ones: an underwater observatory in the US Virgin Islands and the Risør Underwater Post Office in Norway.

You can watch a whole mini-documentary about the post box in Susami on Youtube—we were amazed to learn that there had been over 38,000 special waterproof postcards sent from this underwater post box at the time it was filmed in 2018. I wonder if any Postcrossers have ever sent or received a card from Susami…? Do let us know!

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61 comments so far

Geminiscp, Portugal
So cool!!!!! I wish I can receive one some day! :)
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Tetsuko, Germany
wow. that is really cool. Maybe planning some holidays to go there if one day corona gets back to somekind of normal.

Until then I wait that I might get one card from there :D
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ned44440, Ireland
It would be absolutely fantastic to get a postcard from any of these locations. What a treasure that would be🐬🐳⚓ .
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underthesky, United Kingdom
what a fantastic story! Thank you
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Gen24, United States of America
Amazing! Thanks for sharing!
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ConnieD, Netherlands
A seahorse! So in style! 😂🥰🧜‍♀️🌊📮
https://www.instagram.com/p/BiyMys_lbTM/?igshid=11lk9f0v42ek0
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LuSays, United Kingdom
WOW!!! I have to add this to my bucket list, and send one to myself of course!
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aurelie426, Taiwan
theres also one in Penghu, Taiwan :)
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michelle_2012, France
Wow, I wish I could send a postcard from underwater one day! That' s so cool!
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HFeyzanur, Turkey
Unbelievable. Thans for sharing.👌
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harrickson, United States of America
Fascinating! I wish I knew how to scuba dive!
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Garth94, Canada
Funny timing with this post. I just watched this video last night. A really cool idea!
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lilamint, United States of America
Wouldn’t that be cool if a future archaeologist discovered this, thinking it’s the last surviving artifact of an ancient civilization? 😁
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Norway_girl, Norway
I did send myself a postcard from the underwater post office in Risør some years ago. Couldn't resist it! I dropped the postcard in a mailbox that hung on the wall of the aquarium, and the postcard was then brought down to the underwater post office where it got postmarked.
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mysweetlife63, United States of America
I love this story & the video was great!
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bigred398, Canada
This is really a neat idea, would love to receive a card from any of these fabulous locations.
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Knerq, United States of America
Wow! That's quite amazing.
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apollinette, France
Amazing! what a gift it would be to receive one day a card from under the sea!
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MerlinM, Germany
Whish I could receive one card from those places. Cool story. Thank you for sharing.
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germaju, Brazil
Wow, how amazing! I would like to receive a postcard directly from under the sea, it would be magical!
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Flippie, Canada
I love the story but what to do if you don't dive, like me....?
I'm still waiting for a card from Susami...I let you know, OK
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potatogirl_by, Belarus
Whoa that's incredible! Oh it's a pity I don't know how to swim and dive :( I'm afraid of being in water... It would be superb to send or receive such a wonderful postcard.
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greatoaksstudents, Taiwan
What a coincidence! Yesterday I just got the postcard I mailed to myself from the underwater post box in Penghu, Taiwan. So interesting that you’re discussing the same topic! Mailing it was a fun experience.
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NIDUSKA, Finland
so nice
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Shashidar, India
I hope i recieve a postcard from that Post box atleast once in my life
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Wallaby_Whisperer, Australia
Whilst Vanuatu’s is not the only post box under the sea it was the first...it was there off Efate Island when my parents where working there in 1969. I posted a waterproof card from there to my grandparents.Vanuatu...or as it was known then New Hebrides before Father Walter Lini helped the islands gain independence also has volcano post on Mt Yasur on the island of
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Wallaby_Whisperer, Australia
oops...Tanna Island.
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Kathryn-CO-USA, United States of America
Amazing!
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Blue69, France
I have one. Received by a friend. I m so lucky.
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orca13, Netherlands
Thats cool! Thanks for sharing. I hope i recieve someday a underwater postcard from susami or another place.
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amys2025, United States of America
Amazing!
Hahaha I would like to get a postcard from there or send one
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Swilfong, United States of America
A good reason to get my scuba diving license.
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pamwade, United States of America
No, but I sent several cards from Hell on Grand Cayman Island while scuba diving there. Japan is on my list of places to dive already. This will make it extra special! Thanks for sharing!
Pam
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Talal90Ahmed, Iraq
cooooooool.
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ainu, Germany
Maybe we all can travel again soon...
This is surely now on my list of places to dive.
And thanks to Travel Mode I could send a card then and there :)
Thanks for letting us know about this cool project
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Thea65, Netherlands
Amazing!! Thanks for sharing!
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beesknees, United States of America
Not on my bucket list but good luck to all the brave people that dive
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Robin67, Austria
How cool is that? What a precious card that would be, mailed somewhere under water! ❤️
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Demmi, Romania
So Blue & Cool & Wet!
I wish I will receive a postcard someday from Susami!
Stay safe and keep the water calm!
HAppy postcrossing!
:) :D
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alison41, South Africa
Astonishing! you think you've seen/heard just about everything, but turns out you haven't, not by a long way!
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merryCM, Germany
It was great to come up with such an idea. Who, please, thinks up such ingenious things? Who knows, if the sea level will rise soon, there will certainly be many, many underwater letterboxes. . . if unintentionally. °°°°°blubb°-°blubb°-°blubb°°°
° ° ° ° ° ° ° ° ° ° ° ° ° ° ° °
🐟🐠🐡🦑🐙🦞🦀
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merryCM, Germany
🌎🌏PLEASE, SAFE OUR WONDERFUL PLANET🌎🌏
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Katrina29, Russia
Как было бы здорово получить открытку из под воды! Буду надеяться🤞🤞🤞
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paradonym, Germany
Imagine a postcrosser coming into his office asking for about 100 postcards...
I even had to explain Postcrossing in NYC while purchasing 150 postcards.
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Una2012, Russia
Omg! Soooo coool! I'd like to receive a postcard from under the water some day!
Thank you for amazing story!
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jlk254, United Kingdom
This is so cool!
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Chamakh, Tunisia
Omg ! That’s fantastic. I wish I receive one day an underwater postcard.
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vivian41130, Taiwan
Taiwan also have under water post box!😆🇹🇼
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kotishka666, Belarus
I knew only about Vanuatu since I got 2 postcards form there (one from underwater post office and second is form the volcano as it was stated above). Now I dream to visit Japan and dive into water (i wonder if i can make that with instructor) and send myself a card (i believe it would be the most expensive card ever).
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chasingkites, Russia
Wow!
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Luziaceleste, Brazil
That's why I llove mailboxes postcards, so many varieties! I would love a postcard from one of this.
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ALFAVIT, Russia
I've heard of tin can mail, but this is the first time I've heard about underwater mail. To receive a postcard past an underwater mailbox is a real exotic.)
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ipuenktchen, Iran
never heard about, really fantastic!!!!!!!!!!!!!!!!!!!!!!
lucky ppl who get a card via this box!!!!!!!!!!!!!!!!!!!!!!!
thank for sharing! happy postcrossing, ipue...
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dancingfeet, United States of America
How amazing!
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redtazer2, United States of America
How can I get one of these postcards in The United States?
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Pak2002, United States of America
Can these postcards be purchased in The U.S.?
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buffalo87, United States of America
I wrote many letters under water while stationed on a submarine but of course could not mail them until we surfaced.
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triplightly, United States of America
This world is totally amazing! Thanks for the story.
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runokuono, Finland
thank you for an amazing story ! Almost sad I`m not a diver ❤️
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marjap17, United States of America
Wow! That is amazing. Maybe one day I will get a postcrossing card from there. Loved the video clip. Thanks for sharing!!
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Mosshumla, Sweden
Next summer I'll visit Risør in Norway and send postcards from its Underwater Post Office. Would love to visit the other places as well, but they are a bit too far away.
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