Telescoping riser arrangement forming part of a riser string (1) connecting a subsea well and a floating installation. The riser arrangement is adapted to be switched between a high pressure mode, in which an upper part of the riser assembly will move vertically with respect to the installation when the installation heaves, and a low pressure mode in which the upper part of the riser assembly will move vertically along with the installation when the installation heaves. In the low pressure mode, a low pressure inner sleeve (9) is adapted to reciprocate inside a high pressure outer sleeve (1a), the reciprocating heave path being above the position of the inner sleeve (9) in the high pressure mode. In the high pressure mode, the telescoping section of the low pressure inner sleeve (9) is enclosed within a high pressure compartment.