A sport board for snow sledding or surf body boarding comprises a multi-layered laminated composite foam core coupled with stiffening elements for mechanical strengthening of the board. The composite foam core comprises laminates of polyolefin foam base and stiffening elements composed of substantially polymer foam and has substantial higher compressive strength and flexural strength than the foam base. A front section may be made of the same blank material as the low density polyolefin foam base and is bonded to the front end of the foam core complex to give a full frontal flexibility for a higher directional control by the rider and improved shock absorbing property. Polyethylene foam sheets wrap the foam core complex subassembly and head section for sled integrity and graphic film finishes the sled top, the bottom is also finished with a polyethylene sheet for slickness.