Even when you stay within the no-decompression limit (NDL), a safety stop at around 5 meters (15 feet) before surfacing is generally recommended. How long should you stay there, and how do you read the depth alerts and countdown on your dive computer? This guide covers safety stop depth, duration and technique, and what to do if you miss one.
What Is a Safety Stop in Scuba Diving?
A safety stop is a precaution used in recreational no-decompression diving. Near the end of your ascent, you pause at around 5 meters (15 feet) for at least three minutes before continuing a slow, controlled ascent to the surface.
When you dive on air, your body absorbs nitrogen. As you ascend and the surrounding pressure drops, some of the nitrogen dissolved in your tissues moves into the bloodstream, travels to the lungs and is exhaled. A little extra time in shallow water gives this process more time to work.
A safety stop is different from a mandatory decompression stop. A safety stop is a recommended precaution, while a mandatory decompression stop is required by your dive plan or dive computer. A safety stop is recommended even when the whole dive stays within the no-decompression limit (NDL). For more on the two types of stop and what NDL means, see our NDL article.
Why Is a Safety Stop So Important?
A safety stop gives your body extra time to release inert gas absorbed during the dive, making your ascent more conservative. It's also a chance to check on yourself and your buddy, look at what's above you and prepare for the final ascent.
Essentially it's a buffer, working for inert gas release and as a moment to regroup and focus before you end the dive.
Safety Stop Depth, Duration and When to Do One
Safety stops come down to three related questions: how deep to stop, how long to stay and when to stop. Each needs its own answer, so no single depth or time covers all three.
How Deep Is a Safety Stop?
A safety stop is typically made at around 5 meters (15 feet). Treat this as a reference depth: stay close to it, without chasing an exact reading.
At this shallow depth, lower ambient pressure lets your body continue releasing nitrogen. The stop is an extra precaution during ascent, and other safety concerns always come first. In an emergency, prioritize a safe return to the surface.
How Long Should a Safety Stop Last?
A safety stop should last at least three minutes within the safety stop depth range. The time it takes to ascend to that depth doesn't count toward it.
Those few minutes give your body extra time to keep releasing nitrogen, adding a margin of safety before you surface. Three minutes won't clear all the nitrogen you've absorbed; the stop is simply an added precaution. This duration applies to safety stops on no-decompression dives, separate from mandatory decompression stops.
When Should You Make a Safety Stop?
A safety stop is generally recommended at the end of every dive as an added precaution before surfacing, even when the whole dive stays within the no-decompression limit (NDL).
Plan the stop in advance and keep enough gas in reserve for it. If an emergency occurs, or sea conditions or your remaining gas won't let you complete the stop safely, prioritize a safe return to the surface over finishing the countdown.
How to Do a Safety Stop
-
Plan Your Time and Gas Supply in Advance
Build enough time and gas into your dive plan for the ascent, the safety stop and the return to the surface, and agree on the ascent plan with your buddy. Throughout the dive, keep an eye on your remaining gas and your buddy's condition, and end the dive with plenty of gas in hand rather than starting your ascent once your supply runs low.
-
Make a Controlled Ascent to the Planned Depth
Watch your depth and ascent rate, and ascend slowly and under control according to your training, dive plan and dive computer. As you move into shallower water, vent expanding air from your buoyancy control device (BCD) as needed to keep your ascent from speeding up.
-
Maintain a Stable Position at the Stop
Once you reach the safety stop depth of around 5 meters (15 feet), adjust to neutral buoyancy. Breathe normally and use your instruments to monitor your depth. A reference line, if available, can help you hold position, but keep controlling your buoyancy and watching your depth. Never hold your breath to stay at depth.
-
Monitor Your Progress and Surroundings
Stay within the safety stop depth range for at least three minutes. Keep track of your remaining gas, stay in contact with your buddy and check above you to make sure the way to the surface is clear. If an emergency occurs, or sea conditions or your remaining gas won't let you complete the stop safely, prioritize a safe return to the surface over finishing the stop.
-
Complete the Final Ascent
Once the stop is complete, continue ascending slowly and under control with your buddy, breathing normally throughout. Keep to the required ascent rate all the way up, including after the safety stop ends.
Common Safety Stop Mistakes to Avoid
- Starting the Ascent Too Late: Lingering to watch marine life or take photos leaves less time and gas for the ascent and safety stop, so the end of the dive feels rushed.
- Delaying Buoyancy Adjustments: Waiting until you're already drifting upward to vent air lets the air in your BCD keep expanding, speeding up your ascent and risking an overshoot of the stop depth.
- Holding Your Breath to Maintain Depth: If you ascend while holding your breath, the air in your lungs expands as the pressure drops, increasing the risk of lung overexpansion injury.
- Focusing Only on the Dive Computer: Watching the countdown too closely can mean missing your buddy's condition, your remaining gas or obstacles above.
- Ascending Too Quickly Once the Timer Ends: The relative pressure change grows as you near the surface, so the last part of the ascent must stay slow and controlled too.
- Staying Too Long Despite Low Gas: Never use up the gas you need for a safe return to the surface just to complete the planned stop time. If conditions are no longer safe, surface safely.
How to Read Safety Stop Information on a Dive Computer
On Suunto Nautic, for example, first check your current depth and the up and down arrows next to the stop depth, then check the remaining time, shown in minutes and seconds. Nautic only counts safety stop time while you're within a depth range of 2.4 to 6 meters (7.9 to 20 feet).
In the algorithm settings, you can set a safety stop duration of 3, 4 or 5 minutes, or choose Adjusted, which lets the device adjust the post-decompression safety stop duration to your dive profile.
The countdown responds to your depth. If you descend below 6 meters (20 feet), it pauses, and it resumes once you're back within 2.4 to 6 meters (7.9 to 20 feet). If you rise shallower than 2.4 meters (7.9 feet), an alert prompts you to descend to 3 meters (9.8 feet) or deeper.
When the countdown reaches zero, your dive computer records the safety stop as complete. Continue your ascent slowly and under control according to your dive plan, keeping the same steady pace after the timer ends.
What Happens If You Miss a Safety Stop?
Missing a safety stop doesn't automatically lead to decompression sickness, but feeling fine right afterward doesn't rule out risk either. This matters most if you ascended too quickly or missed a mandatory decompression stop required by your dive computer. In those cases, contact a diving medical professional, explain the details of your dive and share your dive computer records for appropriate guidance.
- Watch for Changes in How You Feel: If you notice unusual fatigue, joint pain, numbness or dizziness after surfacing, stop diving and seek medical evaluation as soon as possible. Take symptoms seriously, even mild ones or ones that seem to ease.
- Get Immediate Help for Severe Symptoms: For serious symptoms such as difficulty breathing or altered consciousness, contact local emergency services immediately. While you wait, trained personnel may give emergency oxygen if it's available and appropriate, but this must never delay rescue or medical transport.
- Stay Out of the Water: Never descend again to make up for a missed stop or to treat symptoms. Follow the guidance of emergency responders or diving medical professionals on what to do next.
Conclusion
A safety stop is an important part of safe diving, and it works alongside any required decompression stops. Follow your dive plan and dive computer, account for how you feel and keep your ascent rate controlled. During the stop, stay aware of your surroundings and your remaining gas. Good habits, built dive after dive, help you manage the risks of diving.
FAQ
What is the hand signal for a safety stop?
A common hand signal for a safety stop involves holding one hand flat and horizontal, palm facing down, to indicate maintaining depth. Hold the other hand below it with three to five fingers raised to show the planned stop duration in minutes. For example, three fingers indicate a three-minute stop, while five fingers indicate a five-minute stop.
Hand signals may vary between training agencies and dive teams, so confirm the signals with your buddy before the dive.
Do you need a rope for a safety stop?
A safety stop does not require a rope. Even without a reference line, divers can complete the stop within the planned depth range by maintaining neutral buoyancy and monitoring their depth with their instruments.
