Abstract: This present utility patent concerns a system of coupling keel for surfboards, which is comprised by keel 1 and lodging 2 with vertical crack 3, retention layer 4, branches 5, lower ended by a closing layer 6 and higher opening 7, by which each tongue-like part 8 of the keel 1 penetrates, and fastening screw 9 of the keel 1, whose contact edge will be lodged in the screw thread 10 of each tongue-like part. Each lodging is provided with saw-edged internal surface 11, in the vertical crack 3, and each keel 1, with tongue-like parts 8, with external face 12 corresponding to the same saw-edged surface, which couple to preserve the original arrangement designed by the manufacturer, and lodgings with external grooves 13, which reduces the possibility of pulling.