Urinal siphon, - with a tubular inlet piece for connecting the urinal siphon to a drain line of a urinal, - with a tubular outlet piece for connecting the urinal siphon to a waste water line, - with a spiral-shaped, tubular intermediate piece, which is interposed between the inlet piece and the outlet piece and which has at least two sections each angled at 180 degrees, - with a sliding sleeve, by means of which the outlet piece is fastened to the inlet piece or the intermediate piece so as to be displaceable relative to the inlet piece by an extension length, characterized in that the urinal siphon comprises a limiting device, by means of which a displacement of the outlet piece relative to the inlet piece beyond the extension length is prevented, wherein the limiting device can be permanently set to an inactive state for disassembly of the outlet piece from the inlet piece, wherein the limiting device is formed by a guide slot, which is aligned parallel to the sliding sleeve at least in the active state, and a guide slot pin, wherein the guide slot pin is in guiding connection with the guide slot at least in the active state of the limiting device, wherein the guide slot is arranged on the outlet piece or the inlet piece so as to be displaceable between an active position and an inactive position, and wherein the guide slot pin is arranged fixedly on the intermediate piece. - with a tubular inlet piece for connecting the urinal siphon to a drain line of a urinal, - with a tubular outlet piece for connecting the urinal siphon to a waste water line, - with a spiral-shaped, tubular intermediate piece, which is interposed between the inlet piece and the outlet piece and which has at least two sections each angled at 180 degrees, - with a sliding sleeve, by means of which the outlet piece is fastened to the inlet piece or the intermediate piece so as to be displaceable relative to the inlet piece by an extension length, characterized in that the urinal siphon comprises a limiting device, by means of which a displacement of the outlet piece relative to the inlet piece beyond the extension length is prevented, wherein the limiting device can be permanently set to an inactive state for disassembly of the outlet piece from the inlet piece, wherein the limiting device is formed by a guide slot, which is aligned parallel to the sliding sleeve at least in the active state, and a guide slot pin, wherein the guide slot pin is in guiding connection with the guide slot at least in the active state of the limiting device, wherein the guide slot is arranged on the outlet piece or the inlet piece so as to be displaceable between an active position and an inactive position, and wherein the guide slot pin is arranged fixedly on the intermediate piece. the urinal siphon comprises a limiting device, by means of which a displacement of the outlet piece relative to the inlet piece beyond the extension length is prevented, wherein the limiting device can be permanently set to an inactive state for disassembly of the outlet piece from the inlet piece, wherein the limiting device is formed by a guide slot, which is aligned parallel to the sliding sleeve at least in the active state, and a guide slot pin, wherein the guide slot pin is in guiding connection with the guide slot at least in the active state of the limiting device, wherein the guide slot is arranged on the outlet piece or the inlet piece so as to be displaceable between an active position and an inactive position, and wherein the guide slot pin is arranged fixedly on the intermediate piece.