A method of installing a subsea riser comprises placing an elongate negatively-buoyant support on the seabed and, when laying the riser on the seabed, guiding a riser portion onto the support to extend along and be cradled by the support. A hogbend region of 5 the riser is then formed by conferring positive buoyancy on the support to lift the support and the riser portion away from the seabed. An element of the support comprises a riser support disposed in a longitudinally-extending open-ended gap between buoyancy volumes disposed on opposite sides of 0 the gap. Coupling formations such as hinge portions can couple the element to a like element. When so coupled, the gaps of those elements align to define an upwardly-opening, longitudinally-extending groove to receive the riser.