Your ascent to the surface is even more critical than your descent. Air spaces expand during ascent, and this can cause overexpansion injuries or decompression sickness if you do not follow safe ascent procedures.

To keep risks of injury to a minimum, ascend no faster than 30 feet per minute. This requires maintaining neutral buoyancy by releasing small amounts of air from your BCD as you swim towards the surface. Never inflate the BCD to lift you to the surface, as this can cause a rapid ascent and serious injury.

Stop your ascent for 3 to 5 minutes when you reach a depth of 15 feet. This is called a safety stop, and allows precautionary decompression before you continue to the surface.

More about decompression sickness and safety stops will be covered later in this site.