Geocaching (pronounced geo-cashing) is a worldwide game of hiding and seeking treasure. A geocacher can place a geocache in the world, pinpoint its location using GPS technology and then share the geocache's existence and location online. Anyone with a GPS unit can then try to locate the geocache.

A geocoin is a special coin created by individuals or groups of geocachers as a kind of signature item or calling card. Like Travel Bugs, each geocoin is assigned a unique tracking ID which allows them to travel from geocache to geocache or to be passed amongst friends, picking up stories along the way. They are bought, sold and traded just like baseball cards or comic books.

There are two types of geocoins:
(1) Trackable geocoins have a 6 digit activation code that is etched into the coin. All trackable geocoins on Geocaching.com will contain the phrase “Trackable at Geocaching.com”. This allows the owner to activate the coin so it has an online profile and icon, it can be logged in and out by various users.

(2) Non trackable geocoins don't have tracking numbers and therefore cannot be logged.

The most common question on etiquette relates to what to do if you find a Geocoin. Keep it? Move it to another geocache? The answer always depends on the goal its owner has set for it. Usually the best way to find the answer to these questions is to visit the geocoin’s personal home page and read the description it contains. If there is a theme or special instructions from the owner you should do your best to adhere to the geocoin’s goal, or send an email to the owner for more clarification. In addition, selling a coin which doesn’t belong to you is generally frowned upon unless you have received express permission from its owner.