Dataset containing 56 stable carbon and oxygen isotope measurements on planktonic foraminifera shells of samples from IODP Expedition 342 Sites U1405, U1406, U1407, U1409, and U1410 in the Northwest Atlantic, spliced to cover the Cenozoic. All samples were measured on a Finnigan MAT 252 gas isotope ratio mass spectrometer coupled to a KIEL III automated carbonate preparation device at MARUM, Bremen. The standard deviation of the in-house standard (Solnhofen limestone) over the measurement period was 0.05 ‰ VPDB for d13C and 0.06 ‰ VPDB for d18O. The columns include sample IDs, corresponding age (sample mid-points), analysed surface dwelling planktonic foraminifera species, as well as raw and corrected stable isotope values. Note that in some cases material of two or three samples had to be pooled in order to acquire enough carbonate material for measurement.