The Sijiao Island is the largest island in the Shengsi Islands with an area of 21.2 km?. The island has subtropical climate with the yearly average temperature of 15.8 °C. It is administrated by Shengsi County , a part of Zhoushan Prefecture .
There are regular ferry lines from Shanghai Wusong, Shiliupu and Luchao Ports operating several times a day. The average travel time from Shanghai is about 5 hours. The island is a touristic destination offering sea bathing.