乘小船的英语是by boat。

例如：

1、The pupils crossed the river by boat.汉语意思：学生们乘小船过河。

2、The island may be reached by boat from the mainland. 汉语意思： 这个岛屿可以从大陆乘小船到达。

3、The only way to get there was by boat. 汉语意思：到那里唯一的方法是乘小船。