Arcus Cloud is the University of Cambridge Research Computing Service’s OpenStack-based scientific cloud platform, providing flexible computing, GPU and storage resources for a wide range of data-intensive research projects. Designed to support cloud-native research workflows, Arcus enables researchers to deploy customised virtual computing environments, scalable data services and advanced analysis platforms tailored to their scientific requirements. Through IRIS, Arcus supports communities including Gaia, Euclid, LSST, PLATO, CASU and SKA-UKSRC, providing a combination of compute capacity, Ceph storage and cloud services for scientific data processing and analysis. Arcus has been a major platform for innovation within IRIS, helping to advance cloud technologies for research and demonstrating how flexible, on-demand infrastructure can support modern scientific workflows across multiple disciplines.