Since 1913, a number of short-term studies have failed to provide comprehensive tidal observations within the Great Bay (Bay). The purpose of this study was to make widespread observations of the tides in and to implement a tidal prediction model of the Bay. With the use of four different tide gauges, calibration against a control gauge was necessary to determine systematic bias. After comparative analysis, each experiment gauge was found to be statistically equivalent to the control gauge. Water level observations were taken at four strategic tide stations in the Bay. The tidal constituents and datums at each station were then derived. Using the NOAA TCARI prediction method, a tide prediction model of the Great Bay was implemented. Verification of the model was made using water level measurements from three spatially and temporally strategic tide stations. The model was found to be statistically significant for tidal predictions within the Bay.