One of the most productive area within the Bay of Brest (located in Northwestern France) is the Daoulas bay - a very shallow embayment (max depth 8 m) - that receives the freshwater inputs of « The mignonne » river. This small bay harbours various aquaculture and fishing activities and also a protected marine area managed by Natura 2000. To better understand physical and biological processes within this bay and their evolution under the context of global change, an observation station has been set up since 2006 on the foreshore in the intertidal zone (https://doi.org/10.17882/42493). In 2016, the SMART Daoulas buoy was deployed nearby to complete the monitoring system. It is a moored buoy located over a flat oyster bed influenced both by marine coastal and fresh waters. On the seabed, various physico-chemical and biological measuring devices are working in continuous and autonomous conditions. The SMART Daoulas station is a component of the national high frequency observing network COAST-HF (http://www.coast-hf.fr) from the ILICO research infrastructure (https://www.ir-ilico.fr) Data are acquired with automatic probes fixed on metallic structure at 50 cm over the sediment bottom. Since 2016, several type of probes were used: DS5 Hydrolab from OTT (http://www.ott.com) ; STPS or SMATCH from NKE (http://www.nke-instrumentation.fr) ; ECO FLNTU, SeaFET V2 and SBE37-SMP-ODO (http://www.seabird.com). The following measured parameters are recorded at 15-mins frequency : sea temperature, practical salinity, total pH, fluorescence and turbidity. Precision estimated of the complete data collection process is : temperature (±0.1°C), conductivity (±0.3mS/cm), in vivo fluorescence (±10%), turbidity (±10%), total pH (± 0.02 pH). The data are qualified into several levels : 0-No Quality Check performed, 1-Good data, 2-Probably good data, 3-Probably bad data, 4-Bad data, 5-Value changed, 7-Nominal value, 8-Interpolated value, 9-Missing value.