This dataset contains the processed temperature data in °C from the ten temperature sensors from 5 to 50m depth along the thermistor chain west of Cap Sicié (Cap Vieux, Toulon, France, 43°02.593N 05°50.616E) deployed between January 2014 and November 2021 (data acquired every 30 min). This dataset is part of the T-MEDNet initiative (www.t-mednet.org), devoted to develop an observation network on climate change effects in marine coastal ecosystems by spreading the acquisition of standard monitoring protocols on seawater temperature and biological indicators over large-scale and long-term.