How deep can you dive without decompression?
There’s a bit of physics and physiology involved in a full explanation, but the short answer is: 40 metres/130 feet is the deepest you can dive without having to perform decompression stops on your way back to the surface.
At what depth do you need to decompress?
The deeper and longer your dive the more chance you need decompression stops. Shallow dives of 6-10 metres (20-30 feet) you can spend over 200 minutes without a decompression stop. Dives to over 30 metres (100 feet) limit your dive time to around 20 minutes before a decompression stop is required.