Siayan Island

Siayan is an uninhabited island of Batanes, the northernmost archipelagic province of the Philippines. Also known as Ditarem Island in the native language, the island is about 1/2 mile to 3/4 miles in diameter and lies about north-northeastward of Itbayat Island.
The closest island is Mavulis Island, which is about north-northeast of Siayan. There are several detached rocks off Siayan's northeastern side, rendering the channel between it and Mabudis unsafe for larger vessels.
Siayan has an elevation of and is listed as an inactive volcano by the Philippine Institute of Volcanology and Seismology.