A rotor assembly for an electric machine, including a rotor core and a shaft, is connected to the rotor core for conjoint rotation, wherein a cooling channel arrangement is formed within the rotor assembly and includes a cooling channel, which extends within the shaft. The rotor assembly further includes a separation element which has a separation portion extending in the circumferential direction at an inner radius of the shaft, wherein the separation portion separates an interior of the shaft into a first shaft portion, in which the cooling channel extends, and into a second shaft portion, wherein the separation element includes a sealing device, which seals off the shaft portions with respect to one another.