I have not tried this underwater as I bought it to be able to use the camera fixed to my motorbike in all weathers. It looks like it will keep the water out and is quite well made. There are however a couple of snags.
Firstly the, so called, tripod bush on the base of the case is not a tripod bush. It is a metric thread so will not fit the old imperial thread used on all tripods. This is annoying as I will now have to make some sort of adaptor to fit it to the camera mount I have on my bike.
Second. The case has a start/stop button but no on/off so it is necessary to turn the camera on before placing it in the case.
Third. Compared with the price of the camera this seems a little pricey