Mount Merapi (2,930m) is an extremely popular overnight trek in Indonesia. It is an active volcano but can be done with little to no experience on the mountains. It is easily accessible from Yogjakarta and usually combined with exploring the cultural city of Yogjakarta.
It is currently closed and not available for hiking. Do check out our other Yogyakarta itineraries or Gunung Merbabu which lies opposite Mount Merapi.