Abstract: A new numerical methodology reaching an improved characterization of the historical harbor wave agitation climate is presented in this work. A detailed frequency-direction wave spectrum definition of wave agitation patterns within harbor basins is achieved, providing an in-depth description of the whole multidirectional and multireflective wave patterns occurring as a natural harbor response. This constitutes an advance from the monoparametric/aggregated wave height parameter-based approaches, traditionally used for wave agitation characterization, to a multivariate and disaggregated representation of in-port waves and the multiple wave transformation processes within harbor basins. In addition, the wave agitation spectral type concept is proposed, whereby the wave agitation spectral shapes are classified into representative clusters of the historical wave agitation response in a harbor. A detailed multiannual analysis of the wave agitation response, based on the different in-port spectral wave components, their relation with the outer-harbor forcing waves, and their interactions with the harbor structures, can be achieved with the proposed methodology. This improved harbor wave climate characterization can be especially relevant for port operability and downtime analyses. The methodology is applied and validated in Africa basin (Las Palmas Port, Spain).