A new cultivar of Hosta named `Atlantis`, a sport of Hosta `Abba Dabba Do`, that is characterized by its unique variegated foliage with green centers and wide yellow-green margins comprising about on third of the leaf area. `Atlantis` is a large Hosta with an upright, mounded habit, a vigorous growth rate, and lavender flowers held on upright scapes in mid summer.