The ETravelSim Peru eSIM works in Aguas Calientes (the base town for Machu Picchu) and across the Sacred Valley towns of Ollantaytambo, Pisac, and Urubamba on the Entel 4G/LTE network. Inside the citadel itself, signal is intermittent for every Peruvian carrier — terrain blocks tower line-of-sight, so use it for photos and offline-map reference rather than live navigation. On the Inca Trail and at Rainbow Mountain, expect long dead zones; download offline maps before you go.