A self propelled trailer for boats or other loads in which the trailer includes two tracked propulsion units. The propulsion units raise to a position adjacent the frame to allow the trailer to be towed by a towing vehicle, and lower to a position in contact with a road surface to allow the operator to move the trailer and its load without being attached to the towing vehicle. In the case of a load that is a boat, the self propelled trailer and the boat could be driven without an attached vehicle, down a boat loading ramp to launch the boat, and be driven with the boat up the boat loading ramp to rendezvous with a towing vehicle in a parking lot. The propulsion units would then be raised into a position adjacent to the trailer frame and the trailer would be towed on the highway.