New distribution records are presented for 19 species of isopods that are recorded for the Mexican Caribbean coast for the first time. The sampling program was conducted in three sites and at three different depths in each site within the Arrecife de Puerto Morelos Nature Reserve. The new records belong to 10 families and 15 genera in the suborders Asellota, Cymothoida and Sphaeromatidea. With the new records included herein isopods could be the most diverse group of peracarid crustaceans found in the Puerto Morelos Reef.