pleasure boat; sightseeing boat; tour boat
A boat used for sightseeing or leisure cruises, often on rivers, lakes, or harbors.
I took a sightseeing boat on Tokyo Bay.
Sightseeing boats operate on this lake.
We rode a pleasure boat on the lake and enjoyed the scenery.
The pleasure boat departs at ten in the morning.
I joined a tour that went around the harbor by pleasure boat.