Thanks for your reply. I am planning on snorkelling. As such, I am
looking at the depth of diving of up to 3 m, and a range of camera of
1-5 m (greater if possible).

I was thinking about an inexpensive camera. I did a search on
dpreview, and found Ricoh G600, which was watreproofed according to
JIS grade 7. This means that the camera can stand 30 minutes at a
depth of 1 m, http://www.opticsplanet.net/water-proof.html . Perhaps,
it could withstand larger depth ? It probably could do it, at a
stretch. Or not ?

Not a chance. Don't even think about it.

Here is the camera Olympus Stylus Tough 8000, which is rated JIS grade
8. This means that it can be continiously immersed into the water at
the conditions more severe than the camera above, JIS grade 7. The
description of Olympus says that the camera is waterproofed up to the
depth 33 ft, or 10 m,
http://www.digicamera.com/reviews/olympus_stylus_8000/
This is what I need !

Probably. I have the Olympus Stylus 1030 SW. It's shock and waterproof to
the depths you're talking about. It's a 10.1 mp camera with some very nice
featues both for underwater and land use. I particularly like it's panorama
feature and its setting specifically for balancing colors underwater.

On the whole, I'd prefer Ricoh G600 because of its better image
quality, if it was waterproof enough.

If you're a good enough photographer to tell the difference, you're good
enough to buy a high end camera.

Lee