Volcán de Agua is the cone that defines Antigua's southern horizon — an almost geometrically perfect stratovolcano rising to 3,760 metres, visible from the city streets and, on clear days, from as far away as Guatemala City. Unlike its neighbours Acatenango and Fuego, Agua is dormant: no eruptions in recorded history since the catastrophic lahar of 1541.
The climb to the summit is achievable in a day, though guides are strongly recommended and some routes require going with a licensed operator due to past robbery incidents on the trail. The reward at the top is a 360-degree panorama taking in the Pacific coast, the highland lakes, and the sprawl of Guatemala City to the east. Night climbs with a sunrise summit are popular, following the same logic as the Acatenango trip. Agua is somewhat easier than Acatenango, making it a good choice if you want the volcano experience without an overnight camp.