Understanding ancient climate dynamics is crucial to accurately forecast future changes to Earth’s climate system. The Norwegian High-Arctic archipelago of Svalbard experiences higher-magnitude warming than the lower latitudes. Its sedimentary succession provides an important climate archive spanning much of the Phanerozoic, including several hyperthermal events and mass extinctions of global importance. These include the End-Permian Mass Extinction (EPME) and the Paleocene–Eocene Thermal Maximum (PETM). In addition, the High Arctic Large Igneous Province (HALIP) provides an opportunity to study how igneous sills interact with organic-rich shales to generate greenhouse gases during contact metamorphism. The ongoing multidisciplinary international project SvalCLIME aims to systematically study these hyperthermal events and their relationships to Phanerozoic climate evolution. SvalCLIME seeks to drill multiple shallow boreholes at four sites in Spitsbergen that will provide a semi-continuous record of Phanerozoic stratigraphy from an underexplored region. The drill cores, in conjunction with outcrops, will provide a Permian–Eocene climate record of unprecedented continuity.</p> <p>Here, we synthesise existing pre-Quaternary Phanerozoic (540–2.58 Ma) paleoclimate and paleoenvironmental data from Svalbard in curated data packages to complement a recently published comprehensive review article. The data packages are organised by proxy, facilitating the addition of future data sets. We present composite data coverage plots of key proxies (stable carbon isotopes [δ<sup>13</sup>C], oxygen isotopes [δ<sup>18</sup>O], pyrolysis, mercury) that illustrate data availability and current data gaps. Further, we give an overview of available geochronological constraints for Svalbard’s pre-Quaternary Phanerozoic rock record, likewise curated into two data collections of 1) various methods that provide age constraints and 2) biostratigraphy. We also discuss the integration of various data sets in four case studies to illustrate the benefit of compiling such data for both drill cores (Longyearbyen CO<sub>2</sub> lab and Deltadalen) and outcrops (Festningen, Lusitaniadalen, Munindalen and Billefjorden).