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Blog > Sending postcards from Germany's deepest postbox!


Sometime ago, we stumbled on this unexpected topic on the forum, where postcrosser Meowpurr tells her adventures of mailing postcards from the deepest postbox in Germany… so of course, we were intrigued and wanted to bring it over to the blog, so that more of you learned about it. Here she is, ready to take us all along on a dive into the deep unknown!

"As someone who loves both postcards and the underwater world, you guys can imagine I’m thrilled to announce that… Germany finally has its own underwater mailbox!

It’s 19 meters deep inside Kreidesee Hemmoor, a lake north of Hamburg, and a genuine Divers’ Disneyland. The water is very clear (for a lake 😉), the lake is ~60m deep, full of things to explore underwater, and it’s only open for divers — no regular swimming allowed! 19 meters deep makes the mailbox significantly deeper than this wonderful place I can’t wait to visit too.

A little over a week ago, a freediving festival took place at the lake, and this is why I was there too. Not knowing anything about the new mailbox, I was busy from mornings to evenings doing workshops, making new friends… Doing regular things like repairing cars…

A diver inspects the engine of a car underwater. The car is covered in algae

… when a diving friend from Berlin texted me that the lake’s Facebook account had just posted the glorious news! I don’t remember ever letting him know about my postcard shenanigans, so I guess I must have given him a drunk post-dive speech about postcards and stamps (I guess you all know what it’s like). Well, good thing I did! I started my little side quest to find the mailbox, and tadaaa:

A German mailbox is seen underwater, hung on a railing

It even states the collection time (“weekly”), tells us that waterproof postcards can be bought at the reception, and that it’s Germany’s deepest mailbox:

A close-up of the collection times posted on the mailbox

The next side quest began because my tight festival schedule hardly allowed me to visit the reception with its constant queue of arriving scuba divers (but of course I made it happen ), and because said reception had screwed up buying waterproof pens for their waterproof postcards! I tested the one they sold me in the sink: came off straight away 😱 They did have a thick green one I could borrow – good enough, but I was so relieved the addresses I drew didn’t have a delicate script like Chinese!

By the time I mailed the cards on the last festival day my legs felt completely useless and I was frozen – it was those cold days in the midst of the heat wave, with only 22°C air temperature and only 12°C in the 20m depth region. Mailing those cards was the very last thing I did before literally breaking down.

The card itself is posted without the stamp, so the diving mail carriers (?) attach it themselves. Of course I reminded the receptionist that international mail requires more postage than national, haha, postcrossers’ paranoia… Would have loved to see their faces when they saw one of their first postcards is going all the way to Vietnam!

Now, this is the card:

A postcard featuring a shark, surrounded by divers

And this is it, Postcrossing reaching new depths! 🎉

Meowpurr is seen underwater, mailing her postcard Meowpurr is seen underwater, mailing her postcard

And there’s a happy ending too: the first card arrived! I can’t wait to go back and mail some more, and I hope I get to spot some more underwater mail on people’s walls!"

Good news! More recently, Meowpurr went back to the lake armed with a few waterproof pens and wrote some more postcards, which have also arrived. At €6 per postcard, this is not a cheap endeavor… but a fun one, for sure! 🤿

63 comments so far

sandhurst, United Kingdom

That is so odd! I wonder how they came up with such an idea.

queenofc, Germany

Fantastic ! Great job, Meowpurr !

Torgo, United States of America

It makes me wonder what the strangest location is for a postbox is in the world! I bet there are some other pretty weird ones out there...

Kanerva, Finland

Cool cards! Thank you Meowpurr for reaching new depths for the sake of Postcrossing, making many postcrossers happy with these special cards and sharing your adventures with all of us.

jjmedusa, United States of America

Wow! This is absolutely fascinating!

Silberdistel76, Germany

So great to read about it here - in fact my husband is the diving postman who empties the box! :-) Now his and my passions seem to get together! ;-)

littleglitterwoman, Germany

Oh Mann, ja, ich habe schon vom Kteidesee gehört. I've already heard of the Kreidesse. But it's new and absolutely cool to me to learn how it has now the same underwater postal system adventure as for example Vietnam or Trinidad (where,, by the way, one of my favourite fish sort, the guppys, stem from). I like how the special flairs of underwater and postal mail can be connected. Who knows, maybe I get to the lake one day and send some little surprise card...

meiadeleite, Portugal

@Silberdistel76 that is so cool!! 😍

aspenone, United States of America

It would be super fun to get a post card from there!

Wynnie, United States of America

That is AWESOME! And of course now I want one. I had never heard of this before - I'll have to have a look-see and find out if the US has their version of this. (Given that all the lobbying for a Postcrossing stamp has not yielded a success there yet, maybe no, but worth checking into). Thanks for sharing!

FairyFoot, United Kingdom

wow, that's just fantastic!

sealed4ever, United States of America


dulcey, United States of America

❤️❤️❤️I love this!!! How special to receive one of these cards! It would be a dream!!

ned44440, Ireland

I love that shark card and hopefully maybe some day I'll be lucky enough to get one. 🙏🙏

TurtleFan, Switzerland

Wonderful story! Great that you put in all that work to make it work.

This reminds me of a geocache I found years ago with a friend that required diving into Lake Michigan. It's on a shipwreck. It was quite an adventure going out to get it. (GC2BG09 for those interested.)

andreabetweentwoseas, Germany

What an idea!!!
How funny! 🤣 😃😆🙃😜😂
Would be great to get such a postcard!!! 😍

Marindananda, United States of America

This is such a great story!
Brilliant and well done meowpurr!!

Steffi67, Germany

Cool story and a great place for a mailbox indeed. I only snorkle, so I wouldn't make it to that maillbox. This indeed could make me dive! Thanks for your Story.

ManxPez7, United States of America

At only 134 or so sent postcards, I’m still in Postcrossing infancy. I’m still dreaming of the day when I receive a card from Africa (or get to send one). But, now - I can add a card from the underwater postbox to my wishlist. I know this is not what Postcrossing is all about. I just can’t help myself. I have that classic “collector mentality” where I’m driven to obtain a sample of just one of everything. This and Antarctica would excite me beyond words!! Great blog!! Thanks for giving us something to dream about!!

LovelySunshine3, United States of America

This is amazing! Love it!

kaila123, United States of America

That is fantastic!! So amazing that anyone came up the idea and then followed through on it. How did the receiver feel?

robinmp, United States of America

Very exciting and thank you for sharing 🤗

snowflake1, Australia

That is soooo cool! ✉️🧜‍♀️ What a great adventure & story. Thanks for sharing Meowpurr 😊

swilldog, United States of America

🤿👀 what a cool place! Added to the list!

AnnJewel_Chyi, China

Wow! Those who receive and those who can dive to send are SOOOOO lucky!! It must also be interesting to be an underwater postman or a post-mermaid!

jeannor, United States of America

Amazing! Thank you for sharing!

kkkkaiyi, China

Thank you for sharing, letting me know that there are such interesting mailing methods in the world!

premkudva, India

So crazy I had known of the one in Vanuatu, now after seeing this turns out there are a few more.

400050, India

Awesomesauce @Meowpurr and great blogpost @meiadeleite! 🙌

ChrisRe, Germany

Really cool...thanks so much for sharing your story and amazing pictures... LOVE IT 📮🌊😃

AlexisAhotep, Portugal

Uauuuu!!! Such a weird & magic place to put a mail box! I wonder how many more could be find all over the underwater world?! 🤭😄
Great adventure @Meowpurr 👏

jeroenvberlo, Netherlands

It waa a lovely surprise getting this card . 😀

Demmi, Romania

Wow, Great Job, @Meowpurr!

hellokathy, Germany

That’s so cool! At first I thought there was a reason for this mailbox to be there (i.e. people living in an underwater station like in a sci-fi movie :D ). But it’s awesome that they do this just so people can use it for fun!

martha66, Netherlands

what a great story and would nt it be lovely to receive this kind of mail, I am all for it! and I hope I receive one in the future.

ClareBerlin, United Kingdom

This was so much fun to read! How amazing and whoever thought of such a thing? Thanks for sharing @Meowpurr

wilmavz, Netherlands

I couldn't believe it, when I read the intro, but it's for real!
Thanks for sharing with us.:)

pandaleppard, United States of America

How wonderful! Thank you to all the innovators and people who use these fun locations. I am not a diver or even a water enthusiast, other than to observe from land. I do fear and respect water and all it's wonderful inhabitants! I also am in awe of all thrill seekers who love to explore dangerous and remote places. Receiving one of these cards would truly be a neat addition and pretty rare as there are not that many places that have this. Thank you for the share!

Coooni, Germany

How crazy and awesome is that!!! I didn't know such a thing existed until today. Maybe one day I'll get a postcard from the depths too :)
Thanks @Meowpurr for the great photos!

Zulhma, Argentina

Amazing story!!!thank you very much!!!

msquared47, United States of America

Very interesting and very cool!

liudiaoyu, Japan

Amazing story!

zwickelzapfer, Germany

Let me just say:
The Kreidesee
is WEST of Hamburg
and NORTH of Bremen
to be exact. ;-) ;-)

cutetaiki, Indonesia

I would love doing this but i can't dive 🥹

HookedonPostcards, Canada

So interesting and unique! Thank you for sharing, and for sharing in such a lovely conversational tone, as well as for including photos. An enjoyable read!

Schamallo, Germany

How incredibly funny and cool at the same time! A reason to start diving. Thank you for this great post. I now imagine a postman with diving equipment in the car who has to go to the lake once a week.

Flippie, Canada

Looooooove the Story!

Mister1975, Germany

Wie lautet die Anschrif dort untern
What's the address?
Commment en ecrire qc

Happy_chen, China

So fascinating and cool!It would be interesting to get a postcard from this mailbox 🤩

VickyGiannopoulou, Greece

Thank you for your amazing story ! Unusual and funny too !

Schwarzwaldalex, Germany

Wow, cool @meowpurr I thaught, this lake was more in the north near the Kreidefelsen at Bad Segeberg. But near Hemmoor... It is nearly a homegame for a Harburger like me :-) It is nice, that this story is share on the main site. Some time ago this mailbox was mentioned in the forum.

PacificNWotter, United States of America

What a treat to get a postcard from the deep! Great article.

isaacna, China

Cool! 👍👍👍

Geminiscp, Portugal

When I first saw this I thought you were talking a 5. geocache! :D LOL, this is even better!

Sending mail from a mine in Poland ( is the best I can achieve. Diving is way out of my league...

@Silberdistel76 congratulations to your husband!!! :)

cl1999, United Kingdom

Wow such a cool thing! Must be so much fun

IndonesiaRaya, Indonesia

I'm interested to have a card @meowpurr and @silberdistel76 😊

beesknees, United States of America

Wow - new meaning of "just going to the mailbox"!

ilysejohnson, United States of America

This is so cool - never knew anything like this existed, and I just love your detailed description and photos! <hahaha - "I guess I must have given him a drunk post-dive speech about postcards and stamps">

Dragongrrl, United States of America

That's amazing! I would love to send a postcard from such a unique location. Time to start hunting!

emoffdayz, United States of America

Wow! , that's just awesome!! Cool postcard too! :)

Saouri, Spain

What a fantasy!. Great place for an unusual postbox.

NerdyUnicorn4, United States of America

My son was reading this over my shoulder and asked, "Why??" My answer - why not?! This is so much fun! I'd love to visit this lake and mail a postcard from underwater. Love the design too.

Leitmann, Israel

Its so funny to think that the German post still works faster under water then my local post! XD

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