The Last Glacial to Interglacial Transition (LGIT) is a period of climatic instability. δ18O records are ideal for investigating the LGIT as this proxy responds rapidly to even minor climatic oscillations. Lacustrine carbonates offer the opportunity to investigate spatial diversity in patterns of climatic change during the LGIT but this requires the generation of δ18O records from a range of latitudinal and longitudinal settings. This study presents a coupled pollen and stable isotopic study of lacustrine carbonates spanning the Windermere Interstadial (the British equivalent of GI1, the Lateglacial Interstadial) from the site of Tirinie in the Scottish Highlands, a region where δ18O records are currently absent. The Interstadial is characterised by three δ18O peaks, warm intervals, and two δ18O declines, cold episodes, the timing of which is constrained by the presence of crypto-tephra. The landscape at Tirinie was highly responsive to these climatic oscillations as the sedimentary and pollen record respond to each isotopic shift. The paper concludes by highlighting that, across the British Isles, lacustrine δ18O records of the Interstadial have a consistent stratigraphy/structure, however, the magnitude of the isotopic shifts are regionally variable. Potential causes of this variability are discussed.