One thousand meters long and 350 meters wide, Sanhsientai is surrounded by steep coral reefs. About two hours are needed to properly see the island, currently reachable via reef at low tide.
三仙台島長一千公尺，寬三百五十公尺，由集塊岩構成，四周有隆起的珊瑚礁包圍，要遊遍全島，約費時二個鐘頭。