A rotary coolant adapter that is compatible with commercially available tool holders attaches to a rotary tool holder to supply coolant to a flow path in a rotary tool. The rotary coolant adapter has a stationary outer housing and a stationary supply tube for supplying coolant to an annular coolant manifold that surrounds a portion of the rotary tool holder. An internal radial feed tube supplies coolant from the annular coolant manifold to the flow path in the tool. Bearings support the stationary outer housing on the rotary coolant holder, and seals are located between the annular coolant manifold and the bearings to prevent coolant leakage from the annular manifold reaching the bearings.