This dataset contains Radium (Ra) and Iron (Fe) concentrations along with supporting oceanographic measurements such as temperature and salinity of the water column. Data are from glacial melt waters around the West Antarctic Peninsula and Greenland as well as from the open southern ocean and at hydrothermal vents along the Mid-Atlantic Ridge. The data were collected for the Radium in Changing Environments: A Novel Tracer of Iron Fluxes at Ocean Margins (RaCE:TraX) project. The RaCE:TraX project is running between June 2017 and June 2022 and uses measurements of Radium (Ra) and Iron (Fe) along with knowledge of the half-life of Ra to predict supply and removal rates of Fe in the marine environment. The results hope to answer the questions 1) how much Fe comes from continental shelf sediments, 2) how much Fe is supplied by glacial meltwater, and 3) how rapidly is Fe scavenged from the metal-rich fluids at hydrothermal vents? Addressing these key gaps in the understanding of the marine Fe cycle will help determine how sensitive marine systems are to current Fe supply, as well as predict the impacts of changes in Fe supply on phytoplankton health, the biological pump, and global climate. The project is led by the University of Southampton School of Ocean and Earth Science and is a collaboration with the University of Bristol. The project received funding from the Natural Environmental Research Council (NERC, grant reference number: NE/P017630/1).