Abstract: A true marine portable boarding platform for the sides of boat hulls and boat transoms that attach to the topside of a hull, gunwale or deck of a boat and also provide three dimensional adjustments for adapting to the various boat designs of different boat manufactuers. The boarding platform consists of wooden planking attached to a stainless steel tubular frame having a padded bumper bar. The platform frame is hinged to the telescopic side sections of a supporting carrier bar in such a way as to allow the platform to fold up within the adjusting tubular framework of the carrier bar. The platform's flexible mounting assembly includes (1) a pair of hangar brackets that are swingably attached to the upper sections of the carrier bar and (2) a pair of self-locking deck plates that are insertibly engaged by the adjusting notched pins located on the opposite inboard ends of the hangar brackets.