This study presents novel information on sponge (Porifera) colonization of artificial substrates in the framework of the LIFE EU Strong Sea Life Project, focusing on the northwestern Sardinian Sea (Western Mediterranean Sea). Five abandoned, lost, or discarded fishing gears (ALDFGs) of the local artisanal fishery from circum-seas of the Asinara Island Marine Protected Area (MPA) were focused. The composition, taxonomic richness, relative abundance, and lifestyle of sponge assemblages are reported. Taxonomic richness is notably high with 2 classes and 13 orders comprising 26 families, 36 genera, and 47 species of Porifera displaying miniaturized body size and dominant encrusting to massive/erect growth forms. New records at species level are reported for the MPA, the Sardinian Sea, and the Western Mediterranean Sea. The successful colonization of the recovered ghost fishing gears by sponges highlights that adaptive strategies of these basal metazoans support their ability to settle and persist on synthetic materials. This dataset contributes to the inventory of (i) recovered ALDFGs in MPAs, (ii) exogenous substrata as suitable substrata for sponge settlement, and (iii) species richness of an MPA and (iv) promotes the biodiversity assessment of the plastisphere in a global context of ocean pollution.