The history of taxonomic studies on Japanese sponges is reviewed. A literature-based list of Japanese sponge species is provided (see Appendix), which includes 636 species plus 16 subspecies, represented by all four classes in the phylum Porifera. Demosponges (Demospongiae) are the most predominant and consist of 434 species, followed by calcareous sponges (Calcarea, 119 spp.), hexactinellid or glass sponges (Hexactinellida, 78 spp.), and homoscleromorph sponges (Homoscleromorpha, 5 spp.). Most of the species are poorly understood, and the taxonomic identity of each species should be investigated in future studies. Haliclona hoshinoi nom. nov. is herein proposed for Haliclona punctata Hoshino, 1981 (type locality: Ariake Sea, Japan) to avoid homonymy with Haliclona punctata Bergquist and Warne, 1980 (type locality: Christchurch, New Zealand).