High school student Atami Kusatsu, on his way to a rural onsen, meets with a tragic accident along the way and dies, but he's reincarnated as an onsen in a fantasy universe. In this world, the liquefied Atami turns out to have remarkable physical and magical healing properties, and he soon finds himself being regularly visited by beautiful elven adventurer Laticia, large-breasted priestess Kumu, and petite village chieftess Chichiku.
Isekai Onsen ni Tensei shita Ore no Kounou ga Tondemosugiru is a completed manga by Nanaumi Sou, first published in 2017. It blends romance, comedy, isekai and fantasy. You can read all 23 available chapters of Isekai Onsen ni Tensei shita Ore no Kounou ga Tondemosugiru online for free on MangaPulse; the newest is Chapter 22, added 2020-12-09. The series is finished, so you can read it from start to end in one go.