Ellie Dyer ventures out into the provinces to join a global treasure hunt. Photograph by Conor Wall.

As I stared up at a large tree set in some remote fields in Kandal province, while simultaneously fending off a nest of red ants and conferring with three confused Cambodian men and a dog, I couldn’t help but wonder how this bizarre situation had come about. The day had started normally enough, until I met up with a friend who offered to take me geocaching.

For the uninitiated, geocaching is a hybrid of ‘geo’, for geography, and ‘caching’, the process of hiding supplies. The phrase was coined in 2000 by Global Positioning System (GPS) users after an enthusiast, computer consultant David Ulmer, decided to test out the accuracy of the technology, and unwittingly sparked a global phenomenon.

Ulmer placed a cache — consisting of a black bucket filled with prizes and a log book — in woods in Oregon, USA, and posted the coordinates of its position online. Within days, two more people had located it using GPS devices, and shared their experiences on the Internet. An explosion of similar activity followed and, soon after, geocaching.com — a website that details the coordinates of hidden caches — was born.

Fast forward to 2013 and geocaching.com has become a world-wide treasure hunt. The website now details more than two million hidden caches,  ranging from tiny containers, called ‘micro-caches’, to larger boxes filled with small tokens. It provides maps and cryptic clues that enable seekers to find them.

One cache has reportedly been placed beyond the Earth’s limits in a locker at the International Space Station, after astronaut Richard Garriott visited in 2008, while another lies 2,300 metres under the ocean near deep-sea hydrothermal vents.

Though less extreme, Cambodia is also part of the global puzzle. At least 30 caches are logged within its borders hidden in spots that include Phnom Penh’s National Museum, Angkor Archaeological Park, Mount Kirirom, Rabbit Island and Kep National Park. But, as with any good treasure hunt, finding them is not always an easy process.

One woman who knows how difficult the hunt can be is Sarah Garbutt, who has had a long-term love affair with geocaching, having looked for them deep in the English countryside as well as inside the Kingdom.

“The best geocache I went to in Cambodia was in the Angkor Wat National Park,” recalls the expat, who has an app on her smartphone that details cache locations, coordinates and clues.

“It was hidden in a small remote temple. The area was amazing and basically deserted, even our tuk-tuk driver was excited as he’d never been there before,” she adds. “Plus the geocache was hidden in the heart of the temple, so you felt like a bit of an explorer.”

Despite her experience, Garbutt admits she sometimes returns to a spot multiple times before finding well-hidden objects. But even if a trip to a cache bears no fruit, the journey can be an adventure in itself. Geocaches are meant to be hidden in beautiful locations or places of general interest.

“The main appeal of geocaching for me is that it gives you a reason and incentive to get outdoors, walking, and it takes you to places you otherwise never would have gone. Plus who doesn’t like a good treasure hunt?” she says.

Geocaching in Cambodia can, however, pose unique challenges, thanks to its weather patterns and a lack of awareness of the practise in populated countryside areas. That can mean caches are removed by people not aware of their purpose or significance.

“Geocaches need to be hidden in areas that will be undisturbed by people and the environment, which can be tough here in Cambodia,” explains Garbutt, who has also planted new caches in the Kingdom for others to find.

“Caches are often lost to the wet season as people planting the caches have not considered the extreme rise of river levels, or predicted that the field will naturally be waterlogged in a few months,“ she adds.

Back to my first experience of geocaching near Takhmao town, and I seemed to be the victim of such a fate. Despite a long and dusty journey into the fields, the tree where the cache is hidden appeared to be empty. My suspicion was confirmed after a petrol seller, who was aware of its hiding place and wandered over to help, and two other local well-wishers also came up empty handed.

Undeterred, I ventured back into central Phnom Penh, complete with several ant bites, to try again. After de-coding a cryptic clue and some time spent pacing the streets, my luck was in. The log books of two well-hidden caches in the centre of town now bear my name. The location of the hidden boxes? Well, you’ll have to find them for yourselves.

How to geocache
Log on to geocaching.com and enter your location. The website will produce a list of nearby caches with varying levels of difficulty, and clues detailing how to find them. Helpful comments logged by previous users are also available. You can load a geo-caching app onto your phone that contains a map to make the search easier. Log on to the website afterwards to register your find, and if you take a small trinket from a cache, remember to add one of your own (but don’t choose anything valuable).