This paper presents a novel robust watermarking algorithm for 3D skinning mesh animations by embedding the watermark in skin weights in addition to key frames. This method can be used for copyright protection, tamper proofing or content annotation purposes. The proposed watermark is immune to noise attacks on key frames and skin weights, key frame dropping and frame modification and is perceptible invisible as well. Experimental results verified that the proposed algorithm has good robustness against attacks and maintains invisibility by preprocessing the animation data sets by key frame decimation.