The Neodymium (Nd) isotopic signature (εNd) has been widely used as a proxy to reconstruct past ocean circulation. Recently it has been increasingly questioned which archives can be reliably used to extract authigenic εNd used for the reconstruction of past ocean circulation and under which environmental conditions bottom seawater εNd are altered and the original water mass signature is overprinted. Pore waters of marine sediments are the key environment in which early diagenetic exchange processes between seawater-derived Nd and terrigenous solid phases take place. This dataset contains Nd isotope compositions of pore water and bottom water from the abyssal Atlantic and Pacific Oceans, focusing on the behavior of the Nd isotope composition in oxic deep-sea sediments during early diagenesis. Samples for the Atlantic were collected during cruise MSM96 in 2020 and for the Pacific during cruises SO239 in 2015, SO240 in 2015, SO268 in 2019, and SO295 in 2022. Seawater samples were taken with NISKIN or GoFlo bottles attached to a CTD water sampling carousel or a bottom water sampler. Pore waters were sampled from MUC liners and several liners were pooled to acquire sufficient volume for isotope analyses. Samples for the Pacific were additionally pooled in the lab to combine several depths and/or nearby stations. Sediments were centrifuged and the supernatant (i.e., the pore water) and the MUC bottom water were filtered through 0.2 µm pore size by different techniques (polyethersylfone syringe filters, cellulose acetate syringe filters, cellulose acetate membrane filters using a water jet pump, nuclepore membrane filters using gas pressure). Additionally, we deployed passive samplers (diffusive gradients in thin film: DGTs) with chelex membranes from DGT Research in MUC liners to sample the pore waters. The different methods lead to different results and based on the comparison and an evaluation of rare earth element concentration data, syringe filtered samples as well as membrane filtered samples not using gas pressure were deemed most reliable. Pore water and seawater was preserved by acidification to ~ pH 1.8 with concentrated ultrapure HCl. Neodymium was purified using first BIORAD AG50W-X8 resin, followed by Eichchrom Ln-spec resin. Samples were measured by MC-ICP-MS.