The genus Lepus is considered a model to investigate ongoing evolutionary processes, as it diverged only 8.61 million years ago. The Alpine mountain hare (L. timidus varronis) is a specialist, and the European hare (L. europaeus) a generalist. In the European Alps, they occur mostly in parapatry, with reported hybridisation. Hybrids can influence evolutionary trajectories, either promoting genetic homogenisation or contributing to the emergence of novel lineages. Differences in foraging behaviour between the two lagomorph species exist, but resource competition appears to occur in overlapping elevations. We investigated dietary ecology of both species and their hybrids, focusing on seasonal and altitudinal differences, in faecal samples collected along altitudinal gradients in Grisons, Switzerland. Dietary composition was inferred for 90 European hares, 59 Alpine mountain hares and 52 hybrids using a DNA metabarcoding approach. We identified 25 orders, 41 families, 93 genera and 88 plant species. Alpine mountain hares showed a selective feeding behaviour selecting plant species typical of the respective elevation. European hares confirmed a more generalist pattern, feeding on different plant taxa irrespective of the elevation, without evidence for dietary restriction toward the end of the vegetation period. Our findings are consistent with the idea that European hares can successfully inhabit Alpine ecosystems and may compete with Alpine mountain hares. In some cases, hybrids exhibited distinct dietary ecology relative to their parental species, resulting in greater overall variability. Hybrids in the Alps might influence evolutionary processes, especially under climate warming, when the parental species gain advantageous dietary traits through backcrossing.