The availability of more powerful mobile devices, sometimes equipped with graphics accelerators, is making it easier to experiment with mobile 3D graphics. In this paper, we exploit the main emerging standard in 3D rendering on mobile devices (OpenGL ES) to build a mobile player (called MobiX3D) for X3D and H-Anim content. The rendering engine of the MobiX3D player supports classic lighting and shading algorithms. We discuss the performance of the player and we apply it to sign language visualization. CR Categories: H.5.1 [Information Interface and Presentation]: Multimedia Information Systems—Artificial, augmented, and virtual realities; I.3.8 [Computer Graphics]: Applications