Coping with a sea level rise, induced by climate change processes, is one of the most important challenges of modern society. It has been projected that, by the end of the 21st century, mean sea level (MSL) will rise between 40 and 60 cm worldwide. Higher MSLs imply that flood risks associated to extreme sea levels (ESLs) will also increase, with the 100-year return levels of extreme events along European coasts projected to increase between 50 and 90 cm by the 2100. ESLs occur due to a superposition of numerous oceanic phenomena which act over different temporal (from seconds to millennia) and spatial scales (from bays to oceans). Within SHExtreme project, contribution of under-researched sub-hourly sea level oscillations to the ESLs along the European coast will be studied. High resolution 1-min sea level data measured at more than 100 tide gauge stations, as well as reanalysis, hindcast and future simulations, will be analyzed to achieve project goals: (i) assessing present day distribution of sub-hourly sea level oscillations and estimating their contribution to the overall ESLs; (ii) linking sub-hourly ESLs to typical synoptic conditions; (iii) estimating future strength and distribution of ESLs related to sub-hourly sea level oscillations. Project SHExtremes will result with the first comprehensive estimate of intensity, frequency, and spatial and temporal distribution of present and future-day sub-hourly ESLs along the European coasts.