The land which now comprises the conservation area was previously declared as a Marine Reserve and Tourist Zone and was placed under the administration and control of the Philippine Tourism Authority in 1978.

It contains numerous islands and islets, such as the chain of Calicoan, Leleboon (Sulangan) and Candolu which form a prolongation of the peninsula.

A prominent feature of the islands is the 400-foot (120 m) coral ridge covered in bushes and shrubs that runs from Guiuan to the southern tip of Candolu in Songi Point.

The dominant vegetation is mangrove (Scyphiphora acidula/nilad and Diospyros ferrea/bantolinao) which lines the coast of mainland Guiuan and covers most of the islands.

Terrestrial species of hardwood trees have also been observed in the larger islands such as Shorea astylosa (yakal), Xanthostemon verdugonianus (mancono), Vitex quinata (colipapa), and Tristaniopsis decorticata (tiga).