Microorganisms associated with olive ridley and East Pacific green turtle nesting and potential cloacal fluid antimicrobial properties were studied in Guanacaste, Costa Rica. During the 2010–2011 season, bacteria and fungi were isolated from olive ridley cloacal fluid, nest chamber sand, and egg samples. Because of the lack of cloacal fluid bacteria isolated, the focus of the 2011–2012 season shifted to determine whether fluid contained antibacterial properties by using Kirby–Bauer disk diffusion assays, and cloacal fluid and sand samples were taken to see whether bacteria were unique to cloacal fluid. Assays were performed on 34 olive ridley and 5 East Pacific green cloacal fluid samples, yielding no zones of inhibition. In the second season, Corynebacterium sp., Bacillus sp., Klebsiella sp., as well as genera documented in previous studies, were found unique to cloacal fluid. Citrobacter freundii and Serratia odorifera are potential contaminates and were common in cloacal fluid and nest chamber sand samples on all beaches. Fungi unique to cloacal fluid included Fusarium sp. and Geotrichum sp., with no previous record of Geotrichum sp. associated with sea turtle nesting. Our results suggest antimicrobial properties either are absent or undetectable by these methods. Future studies should use molecular techniques for bacterial analysis and alternative approaches for detecting antimicrobial properties.