Now several years after the eruption, is Mt. Ontake open for hiking?
It is possible to hike Mt. Ontake but it is still on level 2 alert for volcanic activity so an area approximately 1km wide around the summit is closed. Below is a link to a map (Japanese) of Ontake trails including trail closures.
- The trail from the Tanohara Tourism Center (田の原観光センター) is closed.
- Trails to the peak are closed from Ishimuro Sanso junction (石室山荘) and Nino-ike junction (二ノ池, see also 二ノ池新館, 二ノ池本館).
- The trail between Nyonindo (女人堂) and the San’no-ike evacuation shelter (三ノ池避難小屋) is partially closed.
Also see the Japan Meteorological Agency’s Volcanic Warnings page for up-to-date information regarding volcanic activity.
I hope that helps answer your question!