The study of scyphozoan jellyfishes is crucial due to their significant influence on aquatic environments such as blooming. Species identification is the first step in prediction and management of jellyfish influences. The present paper describes the new records of four scyphozoan jellyfishes in the northern part of the Gulf of Oman. This area has encountered jellyfish blooms in the past. Both morphological studies and the partial genome of the large nuclear ribosomal unit (28S rRNA) and the mitochondrial cytochrome c oxidase I have been sequenced for the collected medusae. The medusae included Cyanea nozakii, Pelagia noctiluca, Chrysaora sp. (Order: Semaeostomeae) and Catostylus sp. (Order: Rhizostomeae).