A small boat has left and right sponsons extending in a longitudinal direction and respectively attached to left and right side walls forming a boat body. The sponsons are provided with an attachment section contacting a left side wall, a gliding section extending substantially horizontally from a lower edge of the attachment section, an inclined section connecting to a side edge of the gliding section, an upper edge of the attachment section, and projecting sections extending from an upper edge to a lower edge of the inclined section. Water flowing along the inclined section is guided by the projection sections and removed or separated from the inclined section. Accordingly, a small boat that turns through a small arc turning locus is provided, e.g., a small boat that is capable of relatively tight turning.