A shock absorbing docking spacer for connecting a vessel to a mooring structure and which includes first and second sections relatively telescopically movable longitudinally relative to one another so as to define a variable effective overall length for the docking spacer and wherein one section contains an airtight air bag and the air bag is connected to the other section such that as the first and second sections move relatively inwardly relative to one another the air bag provides a buffer for absorbing impact forces between the first and second sections brought about by ambient conditions.