Abstract. We investigated the long-term changes of principal tidal component M2 along North Atlantic coasts, from 1846 to 2018. analysed 18 tide gauges with time series starting no later than 1940. The longest is Brest 165 years observations. carefully processed data, particularly remove 18.6-year nodal modulation. found that variations are consistent at all stations in North-East (Cuxhaven, De...