Abstract: A spa and whirlpool conversion system for converting a standard bathtub into a spa or whirlpool wherein the system comprises an enclosure-casing having a standoff or spacing to allow piping, gasket, drain and pump inlet fittings, water jet nozzles, control box, on/off switch, ground fault interrupter and housing case for a pump and adjustable air inlet system. The invention may also include a pump and, or required plumbing lines to facilitate use of the invention. The bathtub enclosure or casing comprises a shell shaped to fit inside of an existing bathtub. The bathtub enclosure can be placed inside or over the bathtub cavity and rests on the gasket. The instant invention may also include plumbing lines and directionally adjustable water jet nozzles.