Sea level is monitored in Spain by various
agencies for different applications: control of the
national levelling system, oceanographic studies,
climate change, operational purpose, harbour
operations, navigation, etc. A general overview of the
Spanish sea level networks is presented in this paper,
as well as the new strategy that is being discussed for
the ongoing sea level monitoring system in Spain. The
sea level data for the period 1990-1999 is examined and
general information about the mean sea level evolution
during that decade. Seasonal variability and tides are
presented.