It has a very rugged topography. The land is generally mountainous and is crisscrossed by numerous streams and rivers. Backed by Cabarian Ridge and the 680-meter high pyramidal Mt. Malasimbo, its 35.25 km-long hilly landmass extends towards the sea and spreads out to a maximum of 13.4 km across. Three mountain ranges covering a total of 11.755 sq-km rise above Puerto Galera's coastal barangays: Mt. Alimbayan in Barangay Balatero, Mt. Talipanan in Barangay Aninuan and San Isidro and Mt. Malasimbo in Barangay Aninuan.
These mountains reach peak elevations of 1,400 meters above sea level and are home to rare animals such as deers, wild boars, monkeys and even the endangered tamaraw (a local buffalo endemic to Mindoro; bubalus mindorensis). Likewise, its numerous mountain springs provide natural habitats to orchid varities such as the tawa-tawa, tiger orchid and mariposa.