The paper combines hydrographic surveying techniques with numerical modelling to evaluate the spatial and temporal distributions of tidal power in a confined channel located in Portugal (Faro Channel in the Ria Formosa). The channel is characterised by strong currents with depth-averaged velocities exceeding 2 m s−1. The model was successfully validated against harmonic analysis data and in situ flow measurements acquired with an Acoustic Doppler Current Profiler (ADCP). Annual estimates of power and energy output were derived, considering spatial and temporal variations in flow velocities and in power density both across and along the channel. The study confirms the relevance of integrating field information with numerical models to achieve a better estimation of tidal power potential through the water column. The accuracy of both bathymetric and tidal elevation data contributes greatly to validating the model; whereas validating the model results with 3D velocity patterns obtained using boat-mounted ADCPs allows peak velocity distributions along the water column and the spatial variation of velocity through different cross-sections to be considered, further assisting in the dynamic placement of tidal energy conversion devices adapted to different resource scenarios. The methodology can be readily adapted and applied to any other inlet, tidal channel, or estuarine mouth.