A scupper joint for a ship includes a body and a nut. The body has a tubular structure as a piece cut from a seamless tube. The tubular structure has a first section and a second section. The first section has a flange at one end thereof as an evagination and a threaded segment at an outer periphery thereof. The second section has at least one annular protrusion at an outer periphery thereof. The nut has an annular structure. The tubular structure has an end evaginated to form a flange and has an inner wall threaded to form a threaded segment. The threaded segment of the nut and the threaded segment of the first section are configured to couple with each other.