As with the second season, the third season is now officially titled Yama no Susume: Third Season (without “tentative”).
The official website for the anime adaptation of Siro’s mountaineering-themed manga Yama no Susume/Encouragement of Climb announced the official title for its upcoming TV anime third season that is slated for summer 2018.
And all of the main staff of the second season are confirmed to return. in the Blu-ray of the OVA “Omoide Present” released today in Japan. episodes have been available on Crunchyroll.