Diving Hand Signals: The Essential Underwater Language

The rules of communication alter radically the instant you go below the surface. You can't talk underwater, at least not in a useful way. That's why diving hand signals become your main way of communicating as soon as your head falls below the waves.

These hand signals are not only helpful for scuba divers and freedivers; they are also necessary for survival. You can use hand signals to monitor how much oxygen is left in your tank, let your diving buddy know when something doesn't feel right, regulate your ascent and descent, and respond quickly in an emergency. They make the difference between a smooth, fun dive and one that could be dangerous.

The good news? Most divers across the world utilize the same basic signals. The basic underwater hand signals have been standardized by groups like PADI, SSI, CMAS, and NAUI. This means that you can dive with people from practically any country and yet be able to talk to them. That being said, there are differences between regions, which is why every pre-dive briefing should include a fast review of the signals.

Execution is the key to good communication underwater. Clear, purposeful gestures made at chest level are more easier to notice than quick or half-formed ones. It's also important to make eye contact. When someone signals you, they need to see you respond, usually with an OK sign, to make sure you got the message.

Here is a simple example of how signals work in real life: You might only need three signals to handle the whole experience on a shallow reef dive. Your friend asks if you're okay with the usual hand gesture, and you say yes. You tap your chest with a closed fist to show that you're low on air twenty minutes later. Your friend agrees, and you both give the thumbs up sign to start your climb. Easy to use, works, and could save a life.

Core “Status” Signals Every Diver Must Know

These are the first signals that new divers learn in entry-level training, and they are the ones that divers utilize the most on every dive they go on.

The “OK” Signal Underwater

The OK hand sign is probably the most important sign you'll ever learn. Make a circle with your thumb and index finger while raising your other fingers. This sign is both a question and an answer. When your friend displays you this sign, they are asking, "Are you OK?" When you flash it back, you're saying "Yes, I'm fine."

This demand response signal keeps buddy teams in touch with each other all the time. You have to answer if someone gives you the signal that it's okay. If you don't respond or stay silent, it's automatically seen as a possible problem.

“Problem / Not OK”

If something isn't right, use a flat hand with the palm down and rock it back and forth like an unstable airplane wing. This lets your friend know right away that you have a problem. Always point to the problem region after this signal. If you're having difficulties equalizing, point to your ears; if your mask is leaking, point to your mask; if you're having trouble breathing, point to your regulator; if you're feeling sick, point to your chest; and if there's a problem with your equipment, point to your gauge.

Surface Signals: A Different Set of Rules

A diving boat or someone far away won't be able to see the same hand signal that you employ underwater. Instead, raise both arms over your head to make a big "O," or tap the top of your head over and over again. Both say you're alright.

If you need support at the surface, wave one arm above your head really fast. Don't wave at boats or other divers on the surface without thinking about it; this could be seen as a request for help.

“I Don’t Feel Well / Something Is Wrong”

This signal fills a hole in traditional signal systems. Put your hands in front of your body and make an oval shape with them, with your fingers pointing toward you. This means you're generally not feeling well; it's not just a small problem, but a feeling that something is really wrong with your body. If a friend sends you this signal, you should take it seriously and start climbing in a controlled way.

“Cold”

Put your arms across your chest and rub your upper arms like you're shivering. Most divers do this with a thumbs up to show they wish to terminate the dive. Hypothermia is a major danger on longer dives, therefore it's important to know when your buddy is too cold.

Real-World Example: A diver starts to go below the renowned USS Liberty wreck while diving in Tulamben, Bali. She has an ear problem at 8 meters and can't clear the pressure. She quickly makes a "problem" sign with her flat palm and rocks it back and forth. Then she points to her ear. Her diving partner gives her the go-ahead with an OK sign, and they both go up a little bit so she can equalize. This simple back-and-forth—problem, point, recognize, adjust—stops what could have been a broken eardrum.

Depth and Movement: Up, Down, Stop, and Level Off

Diving signals govern your position in the water column almost completely. This makes these gestures very important for coordinating with your companion, especially when visibility is low or when you are diving on a complicated multi-level profile.

“Up / End the Dive”

For rookie scuba divers, one of the most crucial things to know is that the thumbs up sign underwater does NOT imply "OK" like it does on land. A hand with the thumb pointed up symbolizes "go up" or "end the dive." With this signal, any diver can call a dive at any moment and for any cause, and their buddy must agree and follow through.

After this thumbs up indication, you should carefully climb at the right speed, which is usually no faster than 18 meters per minute.

“Down / Descend”

A fist with the thumb pointed down is the inverse of the ascension gesture. At the beginning of the dive, use this to consent to start going down, or at depth, use it to advise diving a little deeper. Before you change depth, your partner should give you an OK or the same signal.

“Level Off / Hold This Depth”

A flat hand with the palm down waved softly from side to side. This instructs your friend or dive group to stay at the same depth. You will use this signal a lot when you are at your deepest, at a safety stop, or when you see anything interesting.

“Stop / Hold Position”

Think of a traffic cop directing cars and hold up a flat hand with the fingers pointing forward. In some tricky or overhead situations, divers employ a closed fist with their palm facing forward instead. This is a demand signal: when you see it, everyone in the team stops moving right away until the person who sent it says to do something else.

“Slow Down”

A flat hand going slowly down, like it's pushing down on the water. Scuba diving instructors often utilize this to slow down their students' kicking speed. This saves air and keeps silt from getting stirred up in delicate areas.

“Turn Around / Head Back”

Point your index finger up and make a little circle in the water. Then point back to where you started, the exit line, or the anchor. This means that it's time to start the return leg of the dive.

Ascent & Descent Quick Reference:

• Start descent: Thumbs down, wait for buddy confirmation
• Hold depth: Flat palm, wave horizontally
• Begin ascent: Thumbs up (not an “OK”!)
• Safety stop at 5m: Level off signal + three fingers for 3 minutes
• Surface: Continue ascent after safety stop complete

Air Supply Signals: How Much, Low on Air, and Out of Air

Air management is one of the most important uses of scuba hand signals. Open Water courses teach this skill over and over again because running out of air underwater is one of the most frightening things that can happen to a diver.

“How Much Air Do You Have?”

Put your index finger and middle finger of one hand on the palm of your other hand. This tells your friend to check their gauge and tell you how much air is left. You can either hold up the SPG (submersible pressure gauge) so your friend can view the reading or use your fingers to show the pressure.

“Check Your Air”

Point at your friend and then pretend to look at a gauge on your wrist or console. This signal is used by dive guides to warn clients to keep an eye on their pressure during longer dives, especially with less experienced scuba divers who might get distracted by the underwater world.

“Low on Air”

Put your closed fist on your upper chest. When you get to about 50 bar/500 psi or whatever reserve pressure was agreed upon in the briefing, use this signal. After this signal, you should always give a thumbs up to let your friend know you want to start going up, and they should respond.

“Out of Air”

The universal symbol for "I have no air" is to slice your throat with a flat hand. This is not a subtle gesture; make it explicit and obvious. As soon as you hear this signal, head straight for your friend's spare air source (the spare regulator, which is usually yellow) and get ready to share air as you go up.

“Share Air”

Put your hand in front of your mouth and your friend's mouth, with your palm pointing inside, to imitate the sharing of a regulator. Some agencies teach a different way where you point at the other regulator and then at your friend.

Practical Scenario: At 18 meters deep, two divers are looking around a reef at Koh Tao. The dive has been amazing, but time goes extremely quickly underwater. Diver A taps two fingers on his palm and asks, "How much air?" Diver B checks the gauge and sees that it reads 55 bar. He then puts his fist to his chest to show that he is low on air. Diver A says OK, and then both give the thumbs up. They start to rise slowly and carefully, signaling their safety stop at 5 meters (a flat hand with three fingers) and staying there for three minutes before coming up.

Scuba diving instructors should always make sure that the low on air signal is clear by giving specific reserve pressures in both bar and PSI during every briefing for dive-resort SOPs.

Tip for Dive Centers: Properties using Prostay can embed air-signal explanations and specific pressure rules inside their digital pre-arrival documents and dive-center SOP library.

Buddy, Direction, and Attention Signals

These signals keep the team together and help share discoveries—critical both for safety and for the pure joy of diving with other divers.

“Buddy Up / Stay Together”

Put your two index fingers next to each other so that they contact. This is what guides use to make the space between divers smaller or to put buddy teams back together during a drift dive or when the current gets stronger. Buddy separation occurrences are still one of the most common small concerns in dive safety reports, which makes this simple gesture quite useful.

“Come Here / Come Closer”

Palm facing upward, fingers curling toward your body in a beckoning motion. This is the same signal you’d use on land to wave someone over.

“You Lead / I Lead”

Point at yourself and then point ahead to say, "I'll take the lead." Or, gesture at your friend and then back toward the way you're going to let them lead. This happens a lot on guided shore dives where responsibilities change halfway through.

“Go This Way”

Extend an open hand with all four fingers together, pointing in a direction. Using the full hand rather than just one finger prevents confusion with the “look” signal.

“Look / Look at That”

Point your index and middle fingers at your own eyes, and then point them at something else, such a specimen of marine life, a wreck feature, or something else that interests you. This is how divers tell each other about wonderful things they see without making noise that would scare the animal away.

“Come to My Depth”

Combine the up or down thumb signal with your other hand held flat above or below to indicate the depth change you’re requesting. Essentially: “Come to my level.”

Drift Dive Example: A divemaster takes an 8-person group through moderate current on a wall dive in Cozumel. Every few minutes, she looks back at the group, provides the "buddy up" signal to bring them closer together, and utilizes direction signals to lead them around the reef. A diver at the back sees a huge spotted eagle ray and makes the "look" gesture. The whole group stops, changes the depth a little, and watches the ray glide by, all without saying a word.

Safety Stops, Decompression, and Cramp or Discomfort Signals

Certain signals relate specifically to decompression safety and physical comfort issues that, if ignored, can escalate into serious problems underwater.

Safety Stop Signal

A flat hand with three fingers of the other hand held beneath it is the conventional safety stop signal. It means to stop for three minutes at about 5 meters (15 feet). Some divers just use the "level off" signal and three fingers. The message is the same.

Recreational divers do a safety stop at the end of almost every dive if they follow the right training rules. The Divers Alert Network's research reveals that safety stops can lower the risk of decompression sickness by about 30%.

Decompression / Deco Stop

The "hang loose" gesture (with the pinkie and thumb extended and the other fingers curled) or just the pinkie alone shows that you need to decompress. This is for readers who are used to technical or longer dives. Recreational divers shouldn't plan deco dives without the right training, but knowing this signal on a mixed boat might help avoid confusion.

Cramp

If you feel a cramp, which is usually in your leg or foot, grab the region and say "problem." Your friend might be able to help by gently extending your fin or helping you change your equipment. In this case, your friend's attention can make a difficult moment into a small problem.

“I’m Tired / Need to Rest”

Do a feeble swimming motion with your hands, and then either a flat palm "stop" signal or a pat on your chest. Divers often utilize this at the surface near the diving boat ladder when they need a break before getting out.

“Danger / Abort Dive”

Make a "X" by crossing your arms over your chest with your fists closed. This means there is an urgent risk, and you should give a thumbs up to show that you are going up in a regulated fashion yet quickly away from the danger.

For Dive Resorts and Liveaboards: Prostay can store a single standardized “safety & deco” briefing template, ensuring all guides provide consistent explanations across trips and boats.

Marine Life Hand Signals: Adding Fun to the Dive

The real fun starts once you know the basic safety signals. Divers have come up with a whole set of signals just for telling each other about marine life observations. This lets you tell your friend without generating noise that might scare the animal.

Local dive shops often add their own signals for species that live in that area. You might learn the mola mola (ocean sunfish) signal in Bali. In the Maldives, instructors use certain gestures to show how to act at manta cleaning stations. There are many different types of hammerhead sharks in Cocos Island.

Environmental and Conservation Signals: From “P for Plastic” to Debris Dives

More and more, modern divers are becoming citizen scientists and caretakers of the ocean. Conservation signals are now a part of diving culture, which shows that the undersea world is facing big environmental problems.

The “P for Plastic” Signal

Dutch divers and The Plastic Soup Foundation made this new hand signal popular in 2019. It entails making a "P" shape with your hand or using a version that is approved in your area. If you see plastic trash on the seafloor, use this signal to let your friend know. Since then, PADI AWARE has made this signal stronger over the world.

The problem is urgent: if things keep going the way they are, plastic might exceed fish in the water by 2050. Divers see this huge problem on almost every dive.

“Trash / Debris Here”

Point to the bottom of the ocean and pretend to pick something up and place it in a mesh bag. Many dive centers now have mesh bags just for picking up single-use plastics and other trash while diving for fun.

“Don’t Touch / No Contact”

Point at coral or an animal with your index finger and wag it back and forth. Guides utilize this all the time to keep delicate reef ecosystems safe from well-meaning but possibly detrimental guest touch.

For Dive Operations: Properties using Prostay can:

• Schedule recurring cleanup events (like “Dive Against Debris” days) in the system
• Attach standard hand-signal and debris-handling guidelines to every booking
• Track participation and communicate results to guests post-stay via automated messaging

This turns conservation from an afterthought into an integrated part of the guest experience.

Instructor and Training-Specific Signals

Scuba diving instructors, divemasters, and guides use additional signals during training situations—particularly during Discover Scuba / Try Dives, Open Water courses, and skills practice sessions.

“Watch Me / Look at Me”

Use the standard “look” signal (two fingers to eyes), followed by pointing at your own chest. This tells students: pay attention, I’m about to demonstrate a skill like mask clearing or regulator recovery.

“Kneel / Go to the Bottom”

A flat hand pushing downward, then pointing at the training platform or sandy patch. Used to position students for skills practice in confined water.

“Equalize”

Pinch your nose and mime blowing—the same motion divers use to clear their ears. Often combined with the “problem” signal and pointing at ears when a student is having trouble equalizing on descent.

“Breathe In and Out Slowly”

Hand moving slowly in and out from the mouth area, demonstrating controlled, relaxed breathing. Critical for calming nervous students who may be breathing too fast.

“Repeat Skill / Do It Again”

Make a circle with your index finger and then point at the student. This means they need to practice or test the skill again.

PADI and SSI are two organizations that make illustrated hand-signal cards for teachers. When all of your dive center's instructors use the same set of signals, it makes guests feel much more at ease.

Multi-Property Consistency: Prostay can centralize instructor resources—PDF signal charts, course SOPs, skill demonstration guides—so new staff at any property in your group teach with identical underwater signals, regardless of location.

Communication Beyond Hand Signals: Slates, Lights, and Future Tech

Hand signals form the foundation of underwater communication, but experienced divers supplement them with tools and emerging technology when situations demand it.

Underwater Slates and Wetnotes

When you need to give complicated instructions or emergency information that can't be shown by gestures, employ the "write it down" signal (miming writing on one palm). Take out your slate and write down the message. This is especially helpful for diving briefings at depth or when you need to give specific numbers.

Tank Bangers, Rattles, and Finger-Snaps

You have to catch the other person's attention before you can signal them. Tank bangers (plastic things that snap against your cylinder), rattles, and finger-snaps all provide noise that travels effectively through water. These are very useful when you can't see well or when a friend is recording marine creatures and isn't paying attention.

Dive Lights at Night

Diving at night makes it hard to talk to each other in new ways. The answer is to flash your dive light beam on your own chest or hand while signaling, but never directly in your buddy's eyes. The laser beam makes your gesture clear without blinding others. Most hand signals for night dives are the same as those for daytime dives, except for the lighting.

Full-Face Masks with Communications

Full-face masks with underwater communication devices are used in commercial diving and some advanced recreational training programs. These are still rather rare on regular coral reef pleasure dives, but they are a choice for specialized operations.

Emerging Technology

There are experimental gadgets like "smart gloves" that can recognize gestures with LEDs and AI dive computers that can translate what you see on your wrist. Some people think that by 2030, they might be the norm. But for the foreseeable future, traditional hand signals will still be important and understood by everyone. Technology may fail, but people will always be able to talk to each other.

Night Dive Example: Visibility diminishes to 5 meters when you dive at night on a house reef. Two divers keep close together and use dive lights to light up their own signals. They see a lionfish hunting. One diver taps their buddy's shoulder and uses the "look" signal lit by their beam. They both watch in silence. The light shows the typical low on air indicator at 50 bar. Both agree to make their safety stop (three fingers, level off, three minutes by dive computer) and come up safely near the boat.

Best Practices: Do’s, Don’ts, and Pre-Dive Briefing Checklists

Even experienced divers should routinely update and standardize their signals, especially when diving with new friends or at places they haven't been to before. Never assume that everyone uses the same signal in the same way is good practice.

Key Do’s

• Review hand signals in every pre-dive briefing with your buddy and guide, especially critical signals like “end the dive,” “out of air,” “lost buddy,” and “safety stop”
• Signal slowly, at chest level, with strong movements and direct eye contact
• Respond to every signal you receive—either OK, problem, or the requested action
• Keep one hand reasonably free during most of the dive to be ready to communicate
• Confirm understanding before descending to any certain depth where communication becomes more critical

Key Don’ts

• Don’t use topside meanings underwater—thumbs up means “ascend,” not “great job”
• Don’t invent complex, one-off signals with new buddies right before a deep or drift dive
• Don’t ignore a buddy’s signal, even if you think you understand the situation better—clarify first
• Don’t wave casually at the surface where it could be misread as a distress call

Pre-Dive Hand Signal Checklist for Dive Centers

Learning vital hand signals makes every dive safer and more connected. Clear communication underwater is the most important thing for everyone, whether you're a diver brushing up on your skills or a resort owner trying to make your dive center more consistent.

People who go under the surface can see and do remarkable things in the undersea environment. Make sure you can share those times with your friend without speaking a word.