Technical Abstract: Floating breakwaters are typically used on limited-fetch water bodies, such as lakes, reservoirs, and bays, where wavelengths are relatively short. They are also often preferred for sites with large water level changes. Common uses are to protect small marinas or for shoreline erosion control. While the wave-structure interaction and wave transmission problems can be simulated numerically, laboratory data are often collected to validate model results. In spite of the large amount of work on floating breakwaters, there is still a lack of knowledge on the performance of simple cylinders as floating breakwaters for low-cost bank protection. Here a laboratory investigation of the hydrodynamic interaction of short waves such as are found in small reservoirs with floating breakwaters is described. The breakwater models considered here feature single cylindrical cross-sections or combinations of cylinders joined together with different mooring configurations. A wave flume with a flap-type wave generator and a progressive wave absorber were designed, constructed, and used to investigate the wave transmission characteristics of multiple floating breakwater configurations for regular waves in deep and transitional water depths. When the breakwater models were fixed, the reflection was high compared to the partially restrained models, indicating that the efficiency was strongly dependent on draft and freeboard. For partially restrained models, dissipation had an important role on wave attenuation; therefore, the dynamic response of the breakwater strongly affected its efficiency. For the measured range of waves, zd/d=0.7 was the best of the tested draft ratios for the pile-restrained model It was also observed that horizontal restraint is superior to vertical restraint in terms of improving breakwater efficiency.