Geocaching is a treasure hunting game played outdoors using GPS devices. Players search geocaching websites for caches in their area. Using the coordinates given by the cache owner the players try to find the hidden container. Caches usually contain a log book and a pen or pencil for players to sign with their cache nickname and the date and time. Some caches are bigger containers that might have some collectibles for players to take and leave at their next find, or special geocaching themed items.

Common cache contents are unusual coins, small happy meal type toys, buttons, CDs, or books. Trackable items are moved from cache to cache and tracked online. Trackables will sometimes have goals such as to be placed in a certain cache a long distance from home, or to travel to a certain country, or to travel faster and farther than other hitchhikers in a race. Higher value items are occasionally included in geocaches as a reward for the First to Find (called "FTF"), or in locations which are harder to reach.

Geocache container sizes range from "nanos", which can be smaller than the tip of finger and only have enough room to store the log sheet, 5 gallon buckets or even larger containers. The most common cache containers in rural areas are lunch-box sized plastic storage containers or surplus military ammunition cans. Ammo cans are considered the gold standard of containers because they are very sturdy, waterproof, animal and fire resistant, relatively cheap, and have plenty of room for trade items. Smaller containers are more common in urban areas because they can be more easily hidden.

If a geocache has been vandalized or stolen it is said to have been "muggled". The term plays off the fact that those not familiar with geocaching are called muggles, a term borrowed from the Harry Potter books.

On some occasions players have been approached by police and questioned when they were seen as acting suspiciously. Other times, investigation of a cache site after suspicious activity was reported has resulted in police and bomb squad discovery of the geocache. A number of caches have been destroyed by bomb squads.

Certain types of placements can be problematic. If a hider caches on private property without adequate permission (intentionally or otherwise), it could encourage finders to trespass. If a cache is placed near schools, children's playgrounds, banks, courthouses, or in residential neighborhoods the act of searching can make a finder look suspicious. Hides in these areas are discouraged and cache listing websites enforce guidelines that disallow certain types of placements.

Geocaches come in many different types. From simple "park and dash" that can be found in a few minutes, to extreme caches that need more advance outdoor activities like rappelling or mountain climbing. lists the following types of caches and their descriptions:

  • Traditional Cache
  • Multi-Cache (Offset Cache)
  • Project A.P.E. Cache
  • Mystery or Puzzle Caches
  • Letterbox Hybrid
  • Wherigo™ Cache
  • Event Cache
  • Mega-Event Cache
  • Cache In Trash Out Event
  • EarthCache
  • GPS Adventures Maze Exhibit

Geocaching is a fun outdoor adventure that can be enjoyed by beginner and expert alike. It is a great activity that can be enjoyed by the entire family and give years of entertainment as part of a worldwide community.