This collection activity is the fourth deployment of the SmartBay Observatory. The Observatory was lifted on 25 August 2021 for maintenance and to add a Seabird CTplus sensor, and swap out the pCO2 sensor. 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 Galway Bay 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 publically 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. The Observatory is equipped with a suite of sensors, these include: Acoustic Doppler Current Profiler (ADCP) - Teledyne RDI Workhorse Conductivity-Temperature-Depth (CTD) sensor probe - Idronaut Ocean-Seven 304 plus and Seabird 16 CTplus Acoustic data that have been collected from the SmartBay Observatory site using an icListen HF Smart Hydrophone Video data is streamed in near-real-time from the observatory and also available for download. A WetLabs ECO-FLNTU is installed on the observatory infrastructure. The Galway Bay Observatory is an important contribution by Ireland to the growing global network of real-time data capture systems deployed in the ocean. The purpose of this dataset is to measure and record water currents at the Wave Energy Test Site at an interval of 1m bins through the water column at depth of 25m. These data are used for scientific studies (e.g. Wind and Wave Climate, Marine Technology Development, Water Quality, Noise Environment) and environmental monitoring of the Galway Bay Marine Energy Test Site.