Continuous and long sea level records from four stations along the Canadian Atlantic coast have been examined and analyzed to investigate the seasonal and long‐term changes. Seasonal sea level variations at stations near the open ocean (Halifax, Nova Scotia, and Port‐aux‐Basques and St. John's, Newfoundland) follow mainly the general cycle for subarctic regions, with a low in spring and summer and a high in autumn and winter. Atmospheric pressure, water transport, and the changing density of seawater are found to be the major factors affecting the mean sea level at these stations. The most pronounced effects of river runoff and tides are found at Saint John, New Brunswick, in the Bay of Fundy, with a spring maximum and an