Abstract Sea level variations in the coastal zone can differ significantly from those in the open ocean and can be highly spatiotemporally coherent in the alongshore direction. Yet, where and how coastal sea levels exhibit variations that emerge as persistent and recurrent patterns along the world's coastlines remain poorly understood. Here, we use a Bayesian mixture model to identify large‐scale patterns of coherent modes of monthly coastal sea level variations from coastal altimetry and tide gauge data. We deter…