Purpose of this study is the geophysical validation and performance assessment of standard and newly re-tracked altimeter data in proximity of selected coastlines. Here we analyse the Mediterranean Sea coastal regions using Topex/Poseidon (T/P) and Envisat altimeter data. Applying analogous selection criteria to both type of data. we conclude that Envisat performs better in the coastal regions than TOPEX/Poseidon. At sea-land transitions the performance is better than at land-sea transitions. The correlation between satellite and in-situ sea level anomalies is higher for Envisat than for T/P. Envisat data are retracked with a set of retracking algorithms, an improvement is obtained by using the Beta-5 and the improved retracker methods.