Results show that the global grids of sea level pressure provided by ECMWF operational model, either at 0.25 or 0.125 spacing, or the ERA Interim reanalysis product at 1.5, allow the estimation of the hydrostatic component of the tropospheric delay with an accu-racy of 1 to 3 mm at global scale, provided an adequate model for the height dependence of atmospheric pressure is adopted. In com-parison, for VMF1 grids provided at 2.5 spacing, although the overall accuracy of ZHD estimation is 2–4 mm in most sites, in regions with high variability and strong seasonal signal in the surface pressure, VMF1 can reveal errors with a clear annual pattern and epochs for which the error exceeds the centimetre level. When used to estimate the wet component of the tropospheric delay (zenith wet delay, ZWD) for coastal altimetry, these errors can translate into errors of similar magnitude in sea level studies.