As wolves recolonise their historical range across Europe, ungulates face predation once more – but in landscapes profoundly altered by human activity. This shift raises crucial questions about their capacity to express adaptive antipredator behaviors. Using a quasi-experimental camera-trap design, we examined diel activity responses in ungulates along the ongoing wolf recolonisation in the south-eastern Alps. In summer, red deer gradually increased diurnal activity by 17.6% within a decade of wolf establishment, also heightening activity overlap with humans. This ‘diel shield effect’ disappeared when human hunting occurred. Roe deer adjusted diel activity only to hunting, while Alpine chamois only responded to spatial distribution of outdoor activity. Our findings show that wolf recovery can induce immediate and lasting diel activity shifts in large herbivores, yet responses may strongly depend on species biology and plasticity. Human risk can offset or override these behavioural responses, potentially altering the ecosystemic effects of returning large carnivores.