Controlled ascents and descents are fundamental scuba skills. They help divers manage buoyancy, equalize pressure, stay with a buddy, and monitor the dive profile. Learn and practise these skills with a qualified instructor; this overview is general guidance, not a replacement for hands-on training.
Before you descend
Complete your pre-dive checks with your buddy, confirm that your gas is on and functioning, agree on the dive plan and communication signals, and make sure your weighting and exposure protection are appropriate. Enter the water only when conditions and your team’s experience make the dive suitable.
How to make a controlled descent
- Stay with your buddy. Maintain visual contact and communicate if you have trouble equalizing, controlling buoyancy, or following the planned route.
- Equalize early and often. Use the method taught in your course. Never force an equalization; if discomfort persists, stop the descent, ascend slightly if needed, and signal your buddy.
- Manage buoyancy gradually. Add air to your buoyancy compensator as needed and descend in a controlled manner. Avoid dropping rapidly or using a line as a substitute for buoyancy control.
- Monitor depth, time, and gas. Check your instruments and remain within your training, plan, and the conditions.
How to make a controlled ascent
Ascend slowly and under control, keeping track of your depth and ascent rate on your dive computer or other instruments. There is not one universal rate that should be substituted for every training agency’s guidance and every computer’s settings. Divers Alert Network notes that recommendations vary, while emphasizing that ascents should be slow and controlled. Follow the rate taught by your agency and specified by your equipment, and do not exceed the applicable limit.
As pressure decreases, gas in your BCD or drysuit expands. Vent expanding gas as needed so that buoyancy does not carry you upward faster than intended. Keep breathing normally—never hold your breath—and remain aware of your buddy and surroundings.
Safety stops and decompression stops are not the same
A safety stop is a commonly taught precaution on many recreational dives, when conditions and the dive profile allow it. A required decompression stop is part of a decompression obligation and must be handled according to the training, plan, and equipment used. Do not treat a safety stop as a replacement for required decompression, or assume that every dive has identical stop requirements.
When should you stop or end the dive?
Signal your buddy and follow your training if you have difficulty equalizing, experience equipment problems, lose contact, become unusually cold or distressed, or see gas reserves or conditions depart from the plan. Do not continue simply to reach a target depth or stay underwater longer. If an emergency occurs, follow your training and the dive team’s emergency plan.
Common mistakes
- Descending too quickly or ignoring equalization discomfort.
- Allowing expanding gas to cause an uncontrolled ascent.
- Failing to monitor depth, ascent rate, or gas supply.
- Ascending without coordinating with a buddy when possible.
- Assuming a single numeric ascent rate applies to every situation.
Review DAN’s explanation of ascent rates and its safe-diving practices. Always defer to your current training, dive computer instructions, and the dive plan established before entering the water.
Controlled scuba descents and ascents: practical techniques
A calm descent starts before you leave the surface. Agree on the route and maximum depth with your buddy, check that both divers are ready, and descend where you can maintain contact and equalize comfortably. Add air to your buoyancy compensator only as needed, remembering that gas compresses as pressure increases. Avoid dropping rapidly toward the bottom. If you cannot equalize, stop the descent, signal your buddy, and ascend slightly until the discomfort eases; never force an equalization.
Managing buoyancy on the way up
During ascent, expanding gas can increase buoyancy, so make small, controlled adjustments and monitor your depth and ascent rate. Stay aware of the surface, other divers, currents, and overhead hazards. Follow your dive computer and training-agency procedures. Never hold your breath; breathe continuously. Complete a planned safety stop when indicated and when conditions permit, maintaining buoyancy and buddy awareness throughout.
Common mistakes to avoid
Rushing to catch up with a group, descending without equalizing, grabbing the reef, and dumping or adding BCD gas abruptly can make depth control harder. Practise in suitable conditions with a qualified instructor until you can pause, hover, and make small adjustments. If you feel unwell or cannot control your depth, signal the problem and end the dive safely.