The SmartBay Observatory in Galway Bay is an underwater observatory which uses cameras, probes and sensors to permit continuous and remote live underwater monitoring. It was installed in 2015 on the seafloor 1.5km off the coast of Spiddal, Co. Galway, Ireland at a depth of 20-25m. Underwater observatories allow ocean researchers unique real-time access to monitor ongoing changes in the marine environment. The SmartBay Observatory is an important contribution by Ireland to the growing global network of real-time data capture systems deployed in the ocean. Data relating to the marine environment at the SmartBay Observatory site is transferred in real-time through a fibre optic telecommunications cable to the Marine Institute headquarters and then made publicly available on the internet. The data includes a live video stream, the depth of the observatory node, the water temperature and salinity, and estimates of the chlorophyll and turbidity levels in the water which give an indication of the volume of phytoplankton and other particles, such as sediment, in the water. Maintenance take place on the observatory every 18 to 24 months. A CONTROS HydroC CO2 sensor was installed on the SmartBay cabled Observatory in Galway Bay Ireland in June 2020 (Latitude 53.22733,Longitude -9.26629). The sensor is connected to the fibre and power cable and is transmitting real time high frequency Partial pressure of carbon dioxide {CO2 CAS 124-38-9} {pCO2} data in the water body at 25 m Depth on a continuous basis. Local pCO2 sampling for lab analysis has been carried out at the observatory site to help ground truth the measurements and this work is ongoing in 2021. None