Just put a mask on your face and quietly look into the shallow water, then you will find another wonderful world of Yap. With colorful corals and many fish, big or small, it's possible sometimes to see giant mantas!
Because of its landform, the best way for snorkeling in Yap may be going by boat since it will give you no hustle to reach the most popular snorkeling sites.
On the other hand, stationing on one of the beautiful sandy beaches and swimming across sea grass beds to reach the white sandy bottom with small coral heads covered by many small fish will give you another taste of Yap. You will also enjoy comfortable quietness of the surrounding villages and some cultural points to see.