Disclosed is a guiding device for guiding an elongated element such as a cable or a pipe from the exterior into a hollow interior of a support element, the support element being a support element for supporting an offshore structure and being at least partly submerged in water, wherein the guiding device comprises; a tube having a first opening at a first end for facing the exterior and a second opening at a second end opposite to the first end for facing the hollow interior of the support element. The guiding device is configured to allow water to flow into the first opening and out of the second opening of the tube, and substantially prevent water from flowing into the second opening and out of the first opening whereby the guiding device allows water to enter the hollow interior of the support element but not exit the hollow interior.