Geocaching is described as 'Supercharge your geocaching adventures with the official, full-featured Geocaching App. There are millions of geocaches waiting to be found, scattered throughout more than 185 countries around the world—there are probably even some near you right now' and is an app in the travel & location category. There are more than 10 alternatives to Geocaching for a variety of platforms, including Android, iPhone, Web-based, Windows and iPad apps. The best Geocaching alternative is A Map Of Us, which is free. Other great apps like Geocaching are c:geo, Treasures, Zest Treasure Hunting and Play Munzee.
Treasures is the only open-source AND decentralized alternative to the mainstream geocaching sites. Adventure shouldn't have subscription costs and gatekeepers!