Inter Simple Sequence Repeat (ISSR) and Random Amplified Polymorphic DNA (RAPD) are common PCR-based molecular markers used to study genetic diversity both between and within species. One of important steps in ISSR and RAPD analyses is primer selection to obtain bright PCR products. The aim of this study was to select ISSR and RAPD primers that produced scorable fragments of PCR product for genetic diversity evaluation of seagrass Enhalusacoroides (L.f.) Royle. The study also aimed to compare ISSR and RAPD technique in producing informative fragments. Enhalusacoroides is one seagrass species widely distributed in Indonesia. Seagrass samples were collected from Sanur Coastal Water and from Nusa Dua Coastal Water. DNA was extracted using CTAB method. Ten ISSR primers and eight RAPD primers were tested. Results showed that RAPD was more informative than ISSR. Among ten ISSR primers, only four primers resulted in scorable fragments in all samples, and only one among those primers gave polymorphic pattern. As many as 15 fragments have resulted from three ISSR primers and only 1 fragment was polymorphic. All RAPD primers produced scorable products, and three primers resulted in polymorphic fragments. A total of 42 RAPD fragments were produced and 4 from them were polymorphic fragments