A threaded joint comprises a seal ring positioned between a pin and a box, and located in a groove between the end of a threaded section and the nose of the box. The seal ring has a first base, a second base axially opposite to the first base, at least two protruding annular ribs on the external surface, and an internal surface comprising, in an unloaded position, two frustoconical annular surfaces tapering towards the center of the seal ring and joined by a fillet.