Wetpixel member Dag Leslie Hansen has posted a series of pictures onto the forum showing an attempt to fit the new Canon 5D Mark III into an Aquatica 5D Mark II housing. The short answer is that it doesn’t quite fit! The new camera’s body is deeper and the buttons on the top of the camera do not align with the housing’s controls. Dag seems to feel that if he removes the aperture control gears, he may get the camera in, but will only be able to shoot the camera without exposure adjustment (or possibly in Automatic mode).
If you do not fancy Dag’s DIY approach, is expected that manufacturers will be producing new housings for the 5D Mark III as well as the new Nikon models very soon.