COAST-HF (Coastal OceAn observing SysTem - High Frequency) is a national observation service belonging to the ILICO Research Infrastructure. This network, accredited by the CNRS, aims to federate and coordinate a set of fixed platforms instrumented with high-frequency in situ measurements for key parameters of coastal waters. The POEM buoy is part of this network and is located in the Gulf of Lions in the NW Mediterranean Sea. It's equipped with surface meteorological sensor Airmar and an underwater multi-parametric probe YSI locate at 1.5 m depth. Data are transmitted in real-time to the Coriolis Côtier database. Data are then validated and uploaded on the Seanoe database.