Established in 1933, the Permanent Service for Mean Sea Level (PSMSL) has been responsible for the collection, publication, analysis and interpretation of sea level data from the global network of tide gauges. It is based in Liverpool at the National Oceanography Centre (NOC), which is a component of the UK Natural Environment Research Council (NERC).

The PSMSL is a regular member of the ICSU World Data System. Funding for the PSMSL comes from NERC.

The director of the PSMSL is Dr. Lesley Rickards.