In the present paper, a mesh adaptation process for solving the advection equation on a fully unstructured computational mesh is introduced, with a particular interest in the case it implicitly describes an evolving surface. This process mainly relies on a numerical scheme based on the method of characteristics. However, low order, this scheme lends itself to a thorough analysis on the theoretical side. It gives rise to an anisotropic error estimate which enjoys a very natural interpretation in terms of the Hausdorff distance between the exact and approximated surfaces. The computational mesh is then adapted according to the metric supplied by this estimate. The whole process enjoys a good accuracy as far as the interface resolution is concerned. Some numerical features are discussed and several classical examples are presented and commented in two or three dimensions. Copyright © 2011 John Wiley & Sons, Ltd.