This dataset comprises neodymium (Nd) isotopic compositions measured on 145 samples of aragonitic deep-sea corals from the Drake Passage of the Southern Ocean. Most of the samples were previously collected on expeditions NBP0805 and NBP1103 on the RV Nathaniel B. Palmer. The samples include glacial, deglacial and Holocene aged specimens and most are from 0-40 ka BP (thousand years before present) based on uranium-thorium dating. Neodymium isotope analyses were conducted by either thermal ionisation mass spectrometry (TIMS) or multi-collector inductively-coupled plasma mass spectrometry (MC-ICP-MS) in the MAGIC laboratories at Imperial College London by David Wilson, Torben Struve and Tina van de Flierdt. In the modern ocean, dissolved Nd isotopes are a quasi-conservative water mass tracer, while past compositions of seawater are recorded in deep-sea corals. This dataset therefore provides evidence on the proportions of Atlantic versus Pacific waters admixed in the Southern Ocean through time, which places crucial constraints on global deep water chemistry and circulation dynamics during past climate events. Funding was provided by the NERC grant NE/N001141/1. Related datasets are associated with grant NE/N003861/1. Both grants funded the project "Bridging the Timing Gap: Connecting Late Pleistocene Southern Ocean and Antarctic Climate Records".