Several species of sea urchin share the name green sea urchin:
Lytechinus variegatus, also known as the variegated sea urchin Psammechinus microtuberculatus, occurs in the Atlantic Ocean, Adriatic Sea, Aegean Sea and Mediterranean Psammechinus miliaris, also known as the shore sea urchin Strongylocentrotus droebachiensis, common in northern waters all around the world