Located some 300 km southwest of Angaur, combined with Fanna, as Pulo Anna and Merir, they total an area of 3 square km.
The islands are miniature platforms of reef composed of limestone and sandy soils covered by forest and bush. Along the sandy beaches, coconut palm trees are abundant and were the primary source of copra production on the islands. For culture and history seeking travellers, Sonsorol has the Bai ra Ringal, a registered site for its significance as the place used by the island chiefs for meeting and used as a navigation learning center as well as a place to stay for travellers. Fanna is an uninhabited bird nesting site, while Merir is known for nesting turtles.