File contains, campaigns, events, locations, major and trace elements, H2O, radiogenic and short-lived isotopes of new data along with respective analytical facility for the contribution Identifying fluid-fluxed versus decompression melting in the Tonga island arc - Lau back arc region. The dataset contains new whole rock (n=72) and volcanic glass (n=148) major element, trace element, radiogenic isotope, U-series and volatile data from sampled during R/V Sonne expeditions SO35 (1984), SO67 (1990), SO167 (2002) (Stoffers et al. 2003, doi:10.2312/reports-ifg.2003.20), R/V Southern Surveyor Tonga-Eastern Lau Vents (TELVE, SS02/2003, 2003) and the R/V Nadir NAUTILAU expedition (1989) (Haase et al. 2009, doi:10.1016/j.lithos.2009.05.041). The dataset is discussed in the contribution entitled Identifying fluid-fluxed versus decompression melting in the Tonga island arc - Lau back arc region submitted to Advances in Geochemistry and Cosmochemistry in January 2025. Sampling methods involve ROV Nautile, dredging and grab sampling.The whole rock and glass samples were processed at the same time and in the same facilities as the sample batches discussed in Haase et al. (2002, doi:10.1029/2002GC000335), Haase et al. (2002, doi10.1029/2002GC000335; 2006, doi:10.1016/j.jvolgeores.2005.10.010) and Fretzdorff et al. (2006, doi:10.1029/2005JB003967) using the same methodologies and reference materials.Major elements of glasses were analysed at the Institut für Geowissenschaften, Christian-Albrechts Universität zu Kiel using methods described in Haase et al. (2006, doi:10.1016/j.jvolgeores.2005.10.010) and Fretzdorff et al. (2006, doi:10.1029/2005JB003967). Trace element and Pb isotope analysis for whole rocks and glasses are described in Haase et al. (2006, doi:10.1016/j.jvolgeores.2005.10.010) and Fretzdorff et al. (2006, doi:10.1029/2005JB003967). Major elements of TELVE glasses were analysed using the JEOL JXA-8200 electron microprobe at the GeoZentrum Nordbayern, Erlangen (Beier et al. 2018, doi:10.1007/978-3-642-32226-6_11; Brandl et al. 2012, doi:10.1016/j.chemgeo.2011.12.015). New trace element concentrations on selected samples were analysed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) using an Agilent 7700 quadrupole ICP-MS coupled with a Photon Machines Excite Analyte 193 nm excimer laser ablation system with HelEx sample cell at Macquarie GeoAnalytical, Macquarie University. SRM NIST610 was used for external calibration of relative element sensitivities and 43Ca data for internal calibration. TELVE samples (TD) were analysed in the Helsinki Geoscience Laboratories (HelLabs) using a GeoLas Pro 193 nm ArF laser coupled with an Agilent 7900 ICP-MS. The samples were corrected using SRM NIST610. Uranium-series were analysed on fresh, hand-picked, unaltered volcanic glass samples, which were washed, leached and manually re-inspected twice before the addition of spikes, dissolution and column chemistry described in Beier et al. (2010, doi:10.1029/2010gc003037) and Turner et al. (2011, doi:10.1029/2010gc003403). The samples were analysed at Macquarie University, Sydney, Australia. The U and Th cuts were analysed on a Nu Instruments® MC-ICP-MS following the method described in Dosseto et al. (2006, doi:/10.1016/j.epsl.2006.04.019), and McGee et al. (2011 doi:10.1007/s00410-011-0611-x). Radium cuts were analysed with a ThermoFinnigan Triton® TIMS at Macquarie University, Sydney. Water measurements were performed at the Research School of Earth Sciences at the Australian National University, Canberra, Australia on the SHRIMP-SI.