Despite the acknowledged high diversity of sponges in the Caribbean Sea, calcareous sponges from this region have been poorly studied. In order to start filling this gap, in this study we describe the calcareous sponges from Curaçao, Southern Caribbean. The specimens were collected by SCUBA in eight localities along the island of Curaçao and analysed by morphological and molecular (ITS and C-LSU) approaches. A total of 16 species were found and are described here. Ten species are new to science and are provisionally endemic to Curaçao: Arturia vansoesti sp. nov., Clathrina curacaoensis sp. nov., Clathrina globulosa sp. nov., Grantessa tumida sp. nov., Leucandra caribea sp. nov., Leucilla antillana sp. nov., Leucilla micropilosa sp. nov., Leucandrilla quadriradiata sp. nov., Sycon conulosum sp. nov. and Sycon magnapicale sp. nov. The formerly Brazilian endemic species Borojevia tenuispinata, C. lutea, C. insularis and C. mutabilis have their distribution widened to the Caribbean Sea. Clathrina hondurensis and Leucetta floridana are new records for Curaçaoan waters. With these new records, the diversity of calcareous sponges from the Caribbean Sea reaches 33 species. Some issues on the phylogeny of Calcarea are also discussed.