Tres Reyes Islands is located  in Gasan, Marinduque, Philippines.

Serving as a favorite haunt with delightful picnic grounds and dive spots in Marinduque are these islets named Gaspar, Melchor, and Baltazar, collectively known as Tres Reyes Islands. The islet Gaspar has a short stretch of coral beach with clear blue-green waters ideal for swimming and snorkeling. The second and third islets, Melchor and Baltazar, have precipitous coasts, underwater caves frequented by deep-sea divers. Marine species such as groupers, snappers, mackerels and sweet lips abound in the area, while coconut crabs called igod are commonly found along the beach.

Source:

Visitmyphilippines.com