Safety Stop, Deep Stop & Decompression Stop: What’s the Difference?

Stops during ascent can still be pretty confusing. Safety stops, deep stops, deco stops… what’s the difference, and do you really need them all?

Let’s clear it up so you know exactly when and why to pause on your way back to the surface.

Why Do Divers Make Stops on the Way Up?

Breathing compressed air underwater leads to the accumulation of nitrogen in your body tissues. The deeper and longer you stay, the more nitrogen gets absorbed. When you ascend, the pressure drops, and that nitrogen begins to come back out, a process called off-gassing.

If you ascend too quickly, nitrogen may form bubbles in your bloodstream, like popping open a shaken soda can. This can lead to decompression sickness (DCS), which can range from mild fatigue or joint pain to serious neurological damage.

To help your body release nitrogen safely, divers make specific stops as they ascend. Some are recommended for safety, others are optional, and a few are absolutely mandatory if you exceed certain limits.

Safety Stop : The Smart Pause

• Where: 5 meters (15 feet)

• Duration: 3 minutes

• Why: Gives your body a final chance to off-gas nitrogen before surfacing

• When: Strongly recommended for all dives, especially deeper than 18 meters (60 feet)

💡 You’ll learn all about safety stops and proper ascent techniques in the PADI Open Water Diver Course, and they’ll quickly become part of your routine for safer, smarter diving. Even if your dive computer doesn’t demand it, doing a safety stop is just smart, conservative diving.

Deep Stop : The Optional Buffer

• Where: About halfway between your max depth and the surface (e.g, at 15m if you hit 30m)

• Duration: ~1 minute

• Why: Slows your ascent early, reducing nitrogen buildup and microbubble formation

• When: Optional but often recommended for dives deeper than 25-30 meters or if you’ve had a fast ascent

💡 Think of this as an early “mini-pause” that gives your body a head start before your safety stop. You’ll explore the concept of deep stops and more advanced dive planning in the PADI Advanced Open Water Diver Course, especially during the Deep Adventure Dive.

Decompression Stop : The Must-Do 

• Where: Multiple depths depending on the dive profile, typically ending with a final stop at 3–6 meters (10-20 feet)

• Duration: Varies, depending on how far past the no-decompression limit you’ve gone

• Why: Allows time for nitrogen to off-gas safely during planned decompression dives

Decompression stops are not part of normal recreational diving. They’re more advanced moves used in technical diving that need special training, gear, and certification with a Technical Diving Instructor.

💡That said, recreational divers still need to pay attention, dive tables and computers help you stay within safe no-decompression limits. If you go past those limits, your computer will kick into deco mode and guide you on where and how long to stop.

What to do if you mess up:

• Ascend slowly: never faster than 18 meters (60 feet) per minute. Going even slower adds extra safety.

• Follow your dive computer’s decompression stop instructions exactly

• Remember, going over no-deco limits ups the risk, even if you do the stops right.

💡Important: These “emergency deco stops” are a backup plan, not a target. Don’t make them your norm! Stick to your limits, and if you’re not trained, DECO = NO GO! unless you’re ready to level up to technical diving.

A Quick Scenario

Let’s say you dive to 30 meters for 25 minutes:

• You’re still within your no-deco limit

• Make a deep stop at 15 meters (~1 minute)

• Make a safety stop at 5 meters (3 minutes)

• No decompression stop needed, your profile stayed within safe limits

But if you’d overstayed your bottom time and gone beyond the limit?

• Your computer would enter deco mode

• It would guide you through decompression stops at specific depths and durations

First logged dives or future tech diver? These stops aren’t just boring breaks, they help keep you safe and set you up for many more dives to come!

• Safety stop? Always.
• Deep stop? Great bonus.
• Decompression stop? For trained divers only (or if recreational divers mess up big time.)

Got questions about dive planning or want to learn more about Koh Tao scuba diving? Drop us a message, we’re always happy to chat about dive safety and help you plan your next adventure!