During the last glacial period (~118 to 11.7 ka), the Arctic has been characterized bya major redistribution of flora and fauna as a consequence of extreme climatic fluctua-tions, with associated glacial advances and retreats, sea-level changes, and shifting seaice extent. In the high- latitude regions of Northern Europe that are currently subject torapid climate warming, we lack a comprehensive understanding of faunal biodiversityin the last glacial period due to the extreme rarity of preserved organic remains. Here,we present a stratified sediment deposit with a diverse faunal composition preservedin a bone- bearing layer in Arne Qvamgrotta, part of the Storsteinhola cave system(68.10° N 16.38° E) in Northern Norway. Chronological analyses of sediments andbones including radiocarbon, optically stimulated luminescence, uranium–thorium, andphylogenetic dating place the faunal assemblage in Marine Isotope Stage 5a (MIS 5a,Odderade interstadial, ~85 to 71 ka). Combining comparative osteology and bulk-bonemetabarcoding, we identify 46 taxa, including mammals, birds, and fish, with sev-eral species not previously found in Fennoscandia. The fauna implies a nonanalogouscold- adapted coastal community, with close proximity to sea ice and nearby freshwaterbodies. Mitogenome analyses of a subset of taxa identify extinct lineages which attestto a lack of habitat tracking and the absence of a local refugium during the subsequentfully glaciated periods. This faunal record demonstrates long-term faunal dynamics andcoastal environmental conditions during MIS 5a in the European Arctic.