A fluid swivel for allowing transfer of a fluid across a rotary interface in a swivel rotational central plane between an incoming fluid line and an outgoing product piping; the swivel comprising an inner annular element and an outer annular element, that are located with their adjacent cylindrical surfaces (71, 72) in a close proximity, the inner annular element and the outer annular element defining in the swivel rotational central plane a chamber between the adjacent cylindrical surfaces of the inner and outer annular elements for receiving the fluid, wherein the inner annular element of the swivel is arranged with a connecting conduit to be connected to an end of the incoming fluid line which extends through said element to the chamber for supply of the fluid to the chamber, and wherein the outer annular element of the swivel is arranged to be connected to the outgoing product piping and is provided with a primary duct for transport of the fluid from the chamber to the product piping, wherein the swivel comprises a primary outer reinforcing annular wall arranged adjacent to and around the outer peripheral wall of the outer annular element, the primary outer reinforcing annular wall being arranged with two peripheral centering surface portions (11, 12) for contacting and/or registering with the outer peripheral wall of the outer annular element, the primary outer reinforcing annular wall further being arranged with at least a first central peripheral opening extending along a portion of the periphery of the outer reinforcing annular wall for allowing the primary duct to pass through there, wherein the swivel comprises a primary inner reinforcing annular wall arranged adjacent to the inner peripheral wall of the inner annular element, the primary inner reinforcing annular wall being arranged with two peripheral centering surface portions (21, 22) for contacting and/or registering with the inner peripheral wall of the inner annular element, the primary inner reinforcing annular wall further being arranged with a first central peripheral opening along a portion of the periphery of the inner reinforcing annular wall for allowing the connecting conduit to pass through there, characterized in that the swivel further comprises an upper inner sealing ring, an upper outer sealing ring, a lower inner sealing ring and a lower outer sealing ring; the upper inner sealing ring being mounted on the inner annular element above the swivel rotational central plane; the upper outer sealing ring being mounted on the outer annular element above the swivel rotational central plane with its inner peripheral surface in close proximity with the outer peripheral surface of the upper inner sealing ring; the lower inner sealing ring being mounted on the inner annular element below the swivel rotational central plane; the lower outer sealing ring being mounted on the outer annular element below the swivel rotational central plane with its inner peripheral surface in close proximity with the outer peripheral surface of the lower inner sealing ring; wherein the swivel comprises a secondary outer upper reinforcing ring, a secondary outer lower reinforcing ring, a secondary inner upper reinforcing ring and a secondary inner lower reinforcing ring, wherein the secondary outer upper reinforcing ring is arranged above the swivel rotational central plane and comprises at an inner peripheral surface a secondary peripheral centering surface portion for contacting and/or registering with the outer peripheral wall of the upper outer sealing ring; the secondary outer lower reinforcing ring is arranged below the swivel rotational central plane and comprises at an inner peripheral surface a secondary peripheral centering surface portion for contacting and/or registering with the outer peripheral wall of the lower outer sealing ring; the secondary inner upper reinforcing ring is arranged above the swivel rotational central plane and comprises at an outer peripheral surface a secondary peripheral centering surface portion for contacting and/or registering with the inner peripheral wall of the upper inner sealing ring, and the secondary inner lower reinforcing ring is arranged below the swivel rotational central plane and comprises at an outer peripheral surface a secondary peripheral centering surface portion for contacting and/or registering with the inner peripheral wall of the lower inner sealing ring.