A subsea flexible riser installation has a seabed foundation and a steep-configuration flexible riser anchored to the seabed by the foundation. An attachment formation is fixed relative to the riser and a locating formation is fixed relative to the foundation, both at positions elevated above the seabed. The locating formation is engaged with the attachment formation on the riser. This holds the attachment formation and the riser against movement when engaged, protecting the base of the riser from over-bending and fatigue.