The total emerged area of all four is around 0.19 km2 (0.07 sq mi) and the highest point is 67 metres (220 feet) above sea level.

Volcanism in other areas of the Valencia Trough coast dates between 10 million years and the present and they show a transition from calc-alkaline to alkaline signature.

This, combined with aggressive practices such as the burning of the original bushy vegetation of the lighthouse island (partly for agricultural uses and also to deliberately deprive the numerous endemic snub-nosed vipers of their natural habitat), caused the snakes to become extinct by the end of the 19th century.

The only testimony of their past abundance that remains today is a stuffed viper from the Columbretes in Madrid's Natural Science Museum.

Due to its isolation, the islands are inhabited by an endemic subspecies of small lizard, Podarcis hispanicus atratus.

It covers an area of 400 square kilometres (154 sq mi) where an important community of submarine wildlife thrives undisturbed.