Cocinas and San Pancho Islands, located in the Bay of Chamela, Jalisco, México, are two of the few remaining island ecosystems with little ecological disturbance. We studied both islands aiming to assess their reptile richness. Because the environment in Chamela is seasonal, we conducted biodiversity surveys during six samplings: three in the dry season and three in rainy season. We found a total of seven reptile species on Cocinas and San Pancho Islands representing the first description of their herpetofauna. We recorded four species (Aspidoscelis lineattissima, Hemidactylus frenatus, Iguana iguana, and Urosaurus bicarinatus) on Cocinas Island, and six species (A. lineattissima, Phyllodactylus lanei, H. frenatus, Anolis nebulosus, Urosaurus bicarinatus, and Boa constrictor) on San Pancho Island. Species richness in Cocinas showed a higher evenness than in San Pancho Island. Finally, A. lineattissima and A. nebulosus were the dominant species on Cocinas and San Pancho Islands, respectively.