Variations of Geocaches

There are many types of caches. Some are easy enough to be called "drive-bys," "park 'n' grabs" ("PNGs"), or "cache and dash." Others are very difficult, including staged multi-caches; there are even examples of caches underwater, 50 feet (15 m) up a tree, after long offroad drives, on high mountain peaks, on the Antarctic continent, and above the Arctic Circle. Different geocaching websites choose to list different variations as per their own policies (e.g., Geocaching.com does not list new Webcam, Virtual, Locationless, or Moving geocaches).

Variations of geocaches include:

Traditional: This is the basic cache type. It is a container with a log book (at minimum) found at its listed set of coordinates and usually trade items.
Night Cache: These traditional caches can only be found at night and involve following a series of reflectors with a flashlight to the final cache location.
Event Cache: This is a gathering organised and attended by geocachers. Physical caches placed at events are often temporarily placed for the event date only. The Geocaching events category contains some famous annual Geocaching events.
Cache-In Trash-Out (CITO) Events: This is a variation on event caching. Geocachers gather to clean up the trash in the area to improve the environment as a coordinated activity.
Letterbox Hybrid: A letterbox hybrid cache is a combination of a geocache and a letterbox in the same container. A letterbox has a rubber stamp and a logbook instead of tradable items. Letterboxers carry their own stamp with them, to stamp the letterbox's log book and inversely stamp their personal log book with the letterbox stamp. The hybrid cache contains the important materials for this and may or may not include trade items. Whether the letterbox hybrid contains trade items is up to the owner.
Locationless/Reverse: This variation is similar to a scavenger hunt. A description is given for something to find, such as a one-room schoolhouse, and the finder locates an example of this object. The finder records the location using their GPS handheld receiver and often takes a picture at the location showing the named object and his or her GPS receiver. Typically others are not allowed to log that same location as a find. (This is now part of Waymarking.)
Moving/Traveling: Similar to a traditional geocache, this variation is found at a listed set of coordinates. The finder uses the log book, trades trinkets, and then hides the cache in a different location. By updating this new location on the listing, the finder essentially becomes the hider, and the next finder continues the cycle.
Multi-cache: This cache consists of multiple caches. These caches are one or more intermediate points containing the coordinates for the next or final cache, that contains the log book and trade items.
Mystery/puzzle-based: This cache requires one to discover information in order to find the cache. Generally it includes a false set of coordinates within a mile or a couple of kilometers of the cache, and a puzzle must be solved in order to determine the final cache location. In other cases the given location is correct, but the name of the location or other features found there are themselves a puzzle leading to the final cache. Alternatively, additional information is necessary to access the cache (such as a padlock combination) or there are special requirements for logging the find on-line.
Offset: This cache is similar to the multi-cache except that the initial coordinates are for a location containing information that encodes the final cache coordinates. An example would be to direct the finder to a plaque where the digits of a date on the plaque correspond to coordinates of the final cache.
Virtual: Caches of this nature are coordinates for a location that does not contain the traditional box, log book, or trade items. Instead, the location contains some other described object. Validation for finding a virtual cache generally requires you to email the cache hider with information such as a date or a name on a plaque, or to post a picture of yourself at the site with GPS receiver in hand.
Earthcache: Organized and maintained by the Geological Society of America, the EarthCache program is a subset of geocaching in which the "treasure" a cacher finds is not a physical container with trinkets, but an educational lesson of the Earth. The important requirement for an EarthCache to be approved and published is that the cache listing must contain educational information about the earth science of the cache area, and an interactive educational task which directly engages the cacher in that geology. EarthCaches are submitted at www.earthcache.org, and transferred to Groundspeak’s geocaching.com during the review process. The EarthCache program is funded by Groundspeak, National Geographic, Subaru, and the National Park Service.
Webcam: Similar to a virtual cache; there is no container, log book, or trade items for this cache type. Instead, the coordinates are for a location with a public webcam. Instead of signing a log book, the finder is often required to capture their image from the webcam for verification of the find.