A drop-in mounted bath tub has a peripheral rim that is uniquely shaped to both support the tub on a mounting platform and provide integral handgrips used to assist the bather in entering and exiting the tub. The rim curves out from the top of the basin downward toward the mounting platform. The rim extends down further at the end walls of the basin than at the side walls so that it contacts the mounting platform only at the end walls while being spaced up from the mounting platform at the sides. The contoured rim provides a stable, comfortable surface for the bather to grasp. One or more partition walls extending from the rim between the basin side walls and the outer edge of the rim provides for sealing the basin to the mounting platform as well as keeping items from falling between the tub and the mounting platform and preventing the bather from touching or viewing the rough unfinished outer shell of the basin.