The village offers great possibilities for those who love speleology, as in Ataun there are numerous simas and catalogued caves. They can be two types of karstic systems: active or inactive. Actives are part of the river systems. This is the case of Marumendi, Malkorburu and most of the caves and simas surrounding Alleku, including in this group the cave of Ubegi and the cave of Malkorburu. Inactive, on the other hand, have been originated by the karstification process and are systems that are currently filled with stalactites and stalagmites. The latter are the majority of the cavities of the Ataun Dome.
Ataun is filled with caves and simas, among which the human remains of 5,000 years ago abound: Usategi, Limurita (disappeared when the quarry exploded), Pikandita, Kobazar, Armontaitz, etc.
The cave of Troskaeta is one of the most famous caves in Ataun. It has a length of one kilometer and at the end a beautiful well of water. This cave seems to have been the refuge of bears of the species Ursus spelaeus 20,000 years ago. Thousands of bones of this extinct species have been found.
Considering that speleology practice is a team activity, it is recommended that it be done in a group, with all safety measures and with the appropriate material.