Abstract. Prashad L, Daniel R, Ram M. 2020. Survey of the bacterial diversity at two coastal beaches in Guyana. Biofarmasi J Nat Prod Biochem 18: 1-8. The #63 Beach, Berbice and Marriott Beach, Kingston Seawall, Guyana were surveyed for halophilic bacteria present in its waters. NaCl tolerance, temperature tolerance and antimicrobial activity of isolates against Staphylococcus aureus and Bacillus sp. were tested. Samples of 100 mL were taken from the Shore, 5.0 m, and 10.0 m depth from both locations. The samples were plated and examined for the growth of bacteria of different pigmentation. A total of 4 halophilic isolates were found; 3 from Marriott Beach (Isolates A, B, and G) and 1 (Isolate M) from the #63 Beach. Isolates were of yellow, light orange and pink pigmentation, the 3 isolates from Marriott Beach were, Gram-negative and cocci while the one isolates from #63 Beach were Gram-positive and cocci. The optimum salinity tolerance for the Isolate G from Marriott Beach was 1.5M NaCl, Isolate M from #63 Beach 1.0M NaCl, Isolate B from Marriott Beach 1.0M NaCl and Isolate A from, Marriott Beach 0.5M NaCl. The optimum temperature for the growth of the isolates was 37°C. The isolates had no antimicrobial activity against S. aureus and Bacillus sp.