This data set contains a δ¹⁸O record of the benthic foraminifera C. wuellerstorfi (>250 μm) of gravity core GeoB17426-3 (2.187833'S, 150.860500'E, water depth 1367 m) retrieved northeast off New Hanover, offshore the Bismarck Archipelago, Papua New Guinea. According to the age model of the original publication, the record covers the past 209 kyr and thus, extends back to MIS 7. Oxygen isotope analyses were carried out by the isotope laboratory of MARUM, University of Bremen, on a Finnigan MAT 251 mass spectrometer, which is connected with automatic lines for carbonate preparation. Isotope data were calibrated against the international Vienna Pee Dee Belemnite (VPDB) standard by using an in‐house carbonate standard, which has been calibrated to the National Bureau of Standards 19 standard. The long‐term analytical standard deviation is below ±0.07‰.