This dataset contains dissolved (0.2 μm) barium concentrations ([dBa] and [pBa], respectively), and their stable isotopes (δ¹³⁸Bad and δ¹³⁸Bap, respectively), from the Equatorial Pacific Ocean collected during the GEOTRACES GP11 expedition with the German RV SONNE (SO298). The cruise took place between Guayaquil (Ecuador) and Townsville (Australia) from April to June 2023, with sampling stations extending from Ecuador to Papua New Guinea along the equator. Samples for [dBa] and δ¹³⁸Bad were collected either from the Niskin bottles attached to a stainless steel CTD (SS-CTD) rosette or from a trace-metal-clean underway towed fish. [dBa] was determined by isotope dilution on an Agilent 7500ce Quadrupole-ICP-MS at GEOMAR.Filters for [pBa] and δ¹³⁸Bap were obtained after filtration of seawater collected with the Niskin bottles mounted on a titanium CTD (Ti-CTD) rosette. Particulate samples were first leached to measure labile Ba and then digested to measure refractory Ba concentrations, however only the refractory Ba was analyzed for δ¹³⁸Bap. [pBa] was analyzed on a Thermo Element XR ICP-MS coupled with a CETAC Aridus 2 desolvating nebulizer. The δ138Ba in both dissolved and particulate fractions were determined using a double spike technique on a Thermo Fisher Scientific TM Neptune Plus® Multi-Collector ICP-MS at GEOMAR after chemical purification in the home laboratory. Biogenic silica (bSi) was analyzed in particles (>51 µm) collected using in situ pumps. At coastal stations, a two-step digestion was used to separate biogenic silica (bSi) from silicate minerals. The first digestion extracted bSi (Si1), while the second determined the mineral contribution (Si2). Aluminum concentrations were also measured, and the ratio of Si2/Al2 was used to characterize the silicate mineral fraction. The corrected [bSi] was calculated as: bSi = Si1 – Al1 x (Si2/Al2). At oceanic stations, a one-step digestion was applied to determine bSi directly. Biogenic silica concentrations were analyzed by segmented flow injection with a QUAATRO39 (Seal Analytical), and aluminum concentrations on an Agilent Varian ICP-OES 700 ES.