Compiled radiocarbon dates from marine planktonic foraminifera, are combined with calendar age estimates to derive ocean-atmosphere reservoir age offets, or 'marine reservoir ages', as a measure of evolving ocean-atmosphere radiocarbon disequilibrium. The data span the last ~25,000 years, and derive from the Northest Atlantic, The Iberian Margin, and the Southern Ocean. Cubic spline fits to the compiled data, along with 95% confidence intervals, are included.