A field monitoring study of the Spud Point Marina breakwater was conducted as part of the Monitoring Completed Coastal Projects Program. The breakwater is located within the confines of Bodega Harbor, a relatively protected embayment on the California coast north of San Francisco. The concrete pile-supported structure was selected for monitoring because of its unusual baffled design. Openings in the breakwater below the mean lower low tide level permit relatively unimpeded marina flushing. The baffle panel submergence depth was chosen using theoretical wave height transmission results. A field study of wave transmission was conducted using boat wakes and pressure sensors to measure the generated waves. Soundings of potential scour zones and a side-scan sonar survey were made. Circulation through the breakwater and marina was measured, and the breakwater was examined for structural integrity. Unexpectedly high dissipation of generated waves as they crossed a shallow region fronting the breakwater prevented quantification of wave transmission performance. Flushing performance appeared to be satisfactory. No evidence of scour or structural displacement was found; however, hairline cracks were observed in the cap, which should be monitored as part of future Operations and Maintenance. From this study and other evidence, it appears that the breakwater is giving satisfactory wave attenuation performance. Designers of breakwaters in low-energy environments where flushing performance is critical should consider a baffled structure, although physical model testing may be needed to more confidently predict wind wave and boat wake attenuation. The design approach cannot be deemed more generally applicable, since the contribution of site-specific conditions (particularly the shallow flats fronting the breakwater) to good wave attenuation performance is unknown.