Águas Mornas is a Brazilian municipality in the state of Santa Catarina.
The municipality contains part of the Rio das Lontras Private Natural Heritage Reserve, a fully protected area of montane rainforest in the Atlantic Forest biome. It also contains part of the 84130 ha Serra do Tabuleiro State Park, a protected area created in 1975. The lushly-forested park protects the sources of the Vargem do Braço, Cubatão and D'Una rivers, which supply most of the drinking water for greater Florianópolis and the south coast region.
