Post-modern: the world’s most improbable post offices

From an underwater post office in the Pacific Ocean to a temporary post office at Everest base camp, these are the most improbable post offices in the world. 

Post-modern: the world’s most improbable post offices

From an underwater post office in the Pacific Ocean to a temporary post office at Everest base camp, these are the most improbable post offices in the world. 

Post-modern: the world’s most improbable post offices


From an underwater post office in the Pacific Ocean to a temporary post office at Everest base camp, these are the most improbable post offices in the world. 

UKAHT has been involved in some rather extraordinary postal records over the years. In 2020, we worked with Gerhard Freund, a keen philatelist from South Tyrol in northern Italy, to send a postcard from Port Lockroy to the International Space Station (ISS), the artificial satellite circling 408km (250 miles) above the Earth. The feat represented the first time letters had been sent from Antarctica to space and the first time that polar and space philately had been united on an envelope. 

Then in 2023, we again worked with Gerhard to send a postcard from the world’s southernmost post office at Port Lockroy to the world’s northernmost post office at Ny-Ålesund, a small town in Svalbard, Norway, located well inside the Arctic Circle at 78°56′N. And then, this year, we helped organise a postcard from Port Lockroy to Postojna Cave, the world’s only cave post office.

As such, we thought it was about time we had a look at some of these remarkable institutions. From the seabed to the slopes of Everest, there are seven of the world’s most improbable post offices.

Underwater Post Office, Vanuatu

The Pacific Island nation of Vanuatu, lying 1,750km (1,090mi) to the east of Australia, is home to the world’s only underwater post office. The fully functional, submerged post office is located off the island of Mele at the Hideaway Island resort, a vacation spot popular with scuba divers and snorkellers.

A diver and snorkeller at the underwater post office

The world’s only underwater post office (Credit: Vanuatu Post)

To post a letter, customers will have to purchase waterproof postcards and stamps and have them embossed on land before travelling 50m (15ft) off-shore by boat. From there, they can either scuba or free dive down three meters (9ft) below the surface to the post office. Operational since 2003, the post office receives an estimated 100,00 visitors a year and has its own special edition stamp issue and minisheet. Postal staff take it in turns to scuba down to meet customers. 

Postojna Cave, Slovenia

The jaw-dropping Postojna Cave system, in southwestern Slovenia, is made up of a series of caverns, halls and passages around 24km (15mi) long and two million years old. It is Europe’s most visited cave and has been a popular tourist attraction since 1819 when Ferdinand I of Austria visited the caves. 

Postojna Cave

The world’s only cave post office! (Credit: Postojnska Jama, Archive)

Since then, over 40 million people have come to see the fantastical crystalline galleries dripping with needlelike stalactites and columns of improbable stalagmites. Today, the cave comes with an array of attractions including a railway line, a concert hall and, most significantly, a post office.

In 1899, the world's first cave post office was opened in Postojna Cave. Initially, it was a simple, small, stone building in a chamber called the Dance Hall. In its first year, the post office processed around 7,000 letters but by 1927, when it was renovated and relocated to the much larger Concert Hall, that number had risen to over 90,000. The post office still stands today and is the world’s only cave post office.

Supai Post Office, Arizona, USA

In the Grand Canyon, the US Postal Service still delivers mail by mule. Deliveries by mule first began in the 1930s and continue today. Six days a week, between 10 and 22 mules carry mail, food and supplies down a nine-mile (14.5km) trail to the Havasupai people at the bottom of the Grand Canyon.

The mule train in front of the post office and convenience store (Credit: Elf/CC BY-SA 3.0)

The journey takes around three hours to get down and five hours to get back up. On the return journey, the wrangler untethers the mules and sends them back up on their own. Each pack animal can carry up to 90kg (200lb) and the weight is loaded equally on each side for balance. 

The ‘Mule Train’ postmark (Credit: Coal town guy/CC BY-SA 3.0)

The Supai Post Office, located in Supai Village at the bottom of the valley, has a special Mule Train postmark to celebrate its title as the only mule-led mail route in the USA. According to Daniel Piazza, chief curator of philately at the Smithsonian's National Postal Museum, it is the last official mail-by-mule route in the country, and probably one of the last in the world.

Ny-Ålesund, Svalbard, Norway

The world’s northernmost post office is in Ny-Ålesund, a small town in Svalbard, Norway, located well inside the Arctic Circle at 78°56′N. Ny-Ålesund is the world’s northernmost permanent settlement as well as the world’s northernmost year-round research station. Ny-Ålesund has a permanent population of 35 year-round and 114 in the summer with its residents predominantly hardy scientists and researchers.

Ny Alesund post office on a clear day

The world's northernmost post office in Ny-Ålesund (Credit: HunsaBKK/Shutterstock)

The settlement also has a pedigree in polar exploration. It was here where legendary Norwegian polar explorer Roald Amundsen launched his 1926 expedition to the North Pole aboard the airship Norge. Amundsen reached the Pole and flew on to Teller in Alaska. It was the first verified trip of any kind to reach the North Pole and the first crossing of the Arctic Ocean.

Hikkim Post Office, India

Nestled in the folds of the Himalayas in northern India, the Spiti Valley is one of Earth's most inhabited places. Defined by barren mountains, treacherous passes and winding rivers, the high-altitude, cold desert landscape looks almost otherworldly.

Hikkim Post Office (Credit: Shrey.ashi/CC BY-SA 4.0)

At an elevation of 4,440m (14,400ft), the tiny post office in the village of Hikkim is believed to be the world's highest post office that operates year-round. Two postmen carry the mail by foot on demanding roundtrips of 46km across mountain passes each day to connect a cluster of small villages in this isolated region to the rest of India and the wider world. 

First opened in 1983, the post office was renovated in 2022 to attract more tourists to the village. The new office now occupies a bright-red, letterbox-shaped structure.

Tibetan Paradise Post Office, China

The trek to Everest base camp in Nepal is regularly top of many people's travel bucket lists but Earth’s highest mountain shares a border with China where the world’s highest temporary post office is located. North Everest base camp, China, at an altitude of around 5,100m (16,730ft) above sea level, is home to the Tibetan Paradise Post Office – the highest temporary post office in the world.

North Everest base camp with the post office inset (Credit: Public Domain)

Set up in 2001 to meet the needs of tourists who wanted to send postcards and letters to their families from the Everest base camp, the first China Post office was an old military tent next to the tent guesthouses. In 2008, the post office was upgraded so the Olympic Flame could pass through the station en route to the 2008 Beijing Olympics. 

Then, in 2017, it was upgraded to the Tibet Paradise Post Office, complete with modern facilities, local information and more comfortable amenities. Unlike the Hikkim Post Office in India, the Tibetan Paradise Post Office is not open all year. Instead, it only opens for the trekking and climbing season from mid-April until mid-October. 

Penguin Post Office, Port Lockroy, Antarctica

Okay, so maybe we’re a little biased with this one but we think our beloved Penguin Post Office at Base A, Port Lockroy, is one of the world’s most extraordinary post offices. 

The location has been a safe anchorage since it was first named in 1903. For this reason, in 1944 it was selected as Base A – the first continuously occupied British base in Antarctica as part of the secret wartime mission, Operation Tabarin. Over the ensuing years, Port Lockroy witnessed the birth of British Antarctic science while it operated as an atmospheric research base until 1962. 

A postcard at Port Lockroy

Our beloved Port Lockroy (Credit: UKAHT/Natalie Corbett)

Abandoned for three decades, Port Lockroy was restored in 1996 with support from UKAHT, who then took over full management of the site in 2006. Since then, we’ve been welcoming visitors to the museum and the world’s southernmost public post office, while capturing important data on our resident gentoo colony.

On 11 February 2024, our penguin post office celebrated its 80th birthday. From secret mission to penguin post office, Port Lockroy is an ever-evolving story. We’re looking forward to what the next 80 years have to say.

Support our work Protect Antarctica's heritage

Every membership and donation we receive helps our expert teams deliver vital conservation work across the heritage sites that we preserve. Without your support, sites of great importance in Antarctica's history could quickly deteriorate, taking with them historic artefacts, tales of scientific advancement and human endeavour that inform how we, as a global community, view and value Antarctica today. With your help, we can continue to conserve this special continent to ensure its protection for years to come.

Donate now

Become a member

Follow a unique colony at the end of the world

The gentoos of Port Lockroy are perhaps some of the most famous penguins in the world! The colony made their home with us on Goudier Island over 30 years ago and we have been studying and contributing to their protection ever since. Inquisitive, fluffy and funny, we love sharing their activity with everyone around the world.

Buy now Buy now as gift Renew your adoption