Recently, much effort has been spent in the attempt to provide predictions of physical processes at coastal sites. Numerical models are more and more adopted to characterize hydrodynamics and sediment transport features and their use is encouraged because of their feasible applicability, accuracy and cost. In any way, they need for parameters calibration and validation of results, thus requiring a sensitivity analysis and increasing in turn the demand for rich and comprehensive sets of data. Our work aims to demonstrate that a data approach, besides supporting and improving numerical modelling, has also an additional advantage, i.e. allows to directly identify the key physical processes driving a coastal system as well as to assess their relative strength under diverse conditions. This is especially true in restricted coastal environments, where numerical models could fail because of small spatial scales and fine temporal resolution. In the present case, we illustrate and analyse a unique data set comprising a sequence of detailed measurements of tides, waves and currents, acquired at the same time and location, to infer evidence of recurring patterns and cycles, thus evidencing the possibility to extrapolate these data also in a forecasting perspective. Our method is based on (i) the analysis of temporal trends and variability of hourly-averaged vertical profiles of the current velocity for a variety of tidal conditions; (ii) the spectral analyses of tide levels and water currents measured at different depths; (iii) the computation of the tidal asymmetry factor; and (iv) the harmonic analysis of the tidal constituents. Consequently, details on the vertical structure of the flow, on the correlation between currents and tide, on the tidal asymmetry as well as on flood or ebb dominance are the principal outcomes of this study. Our data approach and results are documented through the detailed study of the Mar Piccolo, a shallow water basin located in the inner part of the Ionian Sea (Southern Italy). While the type of coherent patterns observed are site-specific, the approach and investigation framework are general and may be employed in diverse settings.