Abstract The Western Indian Ocean Province is reckoned for its rich marine diversity; however, sponges of the Mascarene Islands ecoregion are still poorly known. In La Réunion, only three species of class Calcarea have been registered. Hence, calcareous sponges were searched in seven sites representing various habitats of the Western coast of La Réunion, but found in only three of them. A total of 23 sponge samples was identified using morphological and molecular taxonomy. This sampling represents 11 species, all new records for the region, and seven of them are new to science: Ascandra mascarenica sp. nov., A. oceanusvitae sp. nov., Janusya indica gen. et sp. nov., Leucascus tenuispinae sp. nov., Lelapiella tertia sp. nov., Soleneiscus intermedius sp. nov. and Leucandra ornata sp. nov.; and a new genus, Janusya gen. nov.. Based on results from this and from previous studies, we propose the synonymization of the order Murrayonida with Clathrinida. A very low sampling effort has thus increased the number of calcareous sponge species from the Mascarenes Islands ecoregion by 69 % and from La Réunion by 367%.