A pipe insulation jacket comprises two jacket members that can be joined to form a hollow cylinder. Both jacket members are made of a dimensionally stable, thermally insulating material. Both jacket members are provided with an elastic coating layer extending over the inner surface and over one of the radially extending end faces of the jacket members. The outer surfaces of the two jacket members are covered by a common tape linking the jacket members at one side in such a way that they can be spread apart at the other to such an extent that the insulation jacket can be radially moved onto the pipe to be insulated. The tape extends over the jacket member at the side where the two jacket members are spread apart, and its inner side is provided with an adhesive layer to interconnect the two jacket members once the pipe is enclosed.