Sponges compete with other animals and macroalgae for space on rocky substrata. This study investigates the effect of spatial competitors, soft coral Zoanthus sansibaricus and macroalgae Dictyota ciliolata, on tetillid sponge Cinachyrella cf cavernosa. Sponges without competitors (S), sponges competing with the macroalgae (SA) and sponges competing with the hexacoral (SZ) were collected in triplicates, and their transcriptome was sequenced. De novo transcriptome assembly was performed using TransPi pipeline.