This dataset comprises raw downcore plant wax data (compound-specific concentration, δ2H, and δ13C of n-alkanes and fatty acids) from the Rotsee sediment core ROT21. A lake located in Central Switzerland, 47°04′10″N, 8°18′48″E, 419 m a.s.l.), spanning the Late Glacial to Holocene (~12.9–0 ka cal BP). It supports hydroclimate and vegetation reconstructions in Santos et al. (2025, Geophysical Research Letters, in submission), focusing on δ²H values and relative abundances of n-alkanes to derive precipitation δ²Hprc after vegetation corrections.