Abstract: An amphibious catamaran is characterised by the inclusion of two spaced apart hulls (1,2); a framework (3) supporting the hulls; a motor (14) supported by the framework; a drive unit (21) for water propulsion actuated by the motor (14) in use; at least (3) land wheels such as (40-44); two sub-frames (44, 45), each supporting one or more land wheels (40-44); height adjustment means (46; 47) enabling in use one sub-frame, and preferably both sub-frames (44, 45), to be moved with respect to the framework (3) from a position where the land wheels (40-44) stably support the catamaran for travel on land, with the hulls (1, 2) clear of the land, and a position where those of the land wheels (40-44) associated with the moveable sub-frame are raised upwardly above the bottoms of the hulls (1, 2); drive means (not shown but including motor (14)) for land propulsion coacting with one or more of said land wheels (40-44); steering means (not shown) for steering the craft on water and on land; and an input station (59) for