Underwater, you can't talk. Your regulator fills your mouth, your hearing is muffled, and even if you could shout it wouldn't help — sound travels strangely underwater and faces are mostly hidden behind masks anyway. Hand signals are how divers communicate during a dive, and learning them is one of the most important non-physical skills you'll pick up as a new diver. The good news is that the core set is small, intuitive, and standardized across the major dive training agencies, so signals you learn in Punta Cana will work on a dive boat in Indonesia or the Red Sea too. This guide walks through the essential hand signals every diver needs to know — the ones that matter for safety, navigation, gas management, and pointing out marine life — plus a few common mistakes that can cut your dive short or cause real confusion.

New divers sometimes treat hand signals as a formality — something you cover in the classroom portion of the Open Water course and then forget. That's a mistake. Once you're in the water, signals are your only way to coordinate with your buddy and guide, manage emergencies, share what you're seeing, and check that everyone in the group is okay. A dive guide who signals "are you okay?" and gets back a confused stare or the wrong signal will often abort the dive — not because anything is wrong, but because they can't confirm that everything is right. Knowing the signals fluently lets the whole group dive deeper, longer, and more enjoyably.

The standard hand signals were originally codified by the Recreational Scuba Training Council and PADI and are used in nearly identical form by SSI, NAUI, SDI, and other major agencies. There are some regional variations and some operator-specific gestures, but the core set covered below is universal. PADI also added an official new signal in 2023 — "I don't feel well" — to address a gap that had bothered the dive medical community for years.

OK / Are you OK? Make a circle with your thumb and forefinger, three remaining fingers extended upward. This is both a question and an answer. Your guide will signal this to you regularly throughout the dive, and you must respond with the same signal to confirm you're fine. Don't ignore it. Don't just nod — nodding is hard to see and not standardized. Always answer with the same gesture. If you don't respond, your guide may move to check on you, which interrupts the dive for everyone.

Up / End the dive. Thumbs up. This does not mean "OK" — this is the single most important fact about scuba hand signals and the most common cause of confusion among new divers. A thumbs-up underwater means "I want to ascend" or "let's end the dive." If you give a thumbs-up to acknowledge something nice, your guide will start heading you to the surface. To signal OK, use the OK circle described above. To signal that you genuinely want to end the dive, use the thumbs-up.

Down / Let's descend. Thumbs down. Used at the start of the dive to signal that everyone is ready to descend, and occasionally during the dive if the group is moving deeper. Like thumbs up, this is a directional command, not a comment on quality.

Something is wrong (general). Hand flat, palm down, rocked side to side like a wobbling boat. This is the "there's a problem" attention-getter. After making it, point to whatever the problem is — your ear, your regulator, your buddy. Used to flag an issue that isn't yet a full emergency.

Out of air. Flat hand drawn horizontally across the throat in a cutting motion. The most serious in-water signal. If you see this from another diver, immediately offer your alternate air source (octopus regulator). If you make this signal, your buddy or guide will share air with you and begin a controlled ascent. This is the universal panic-button signal — don't use it casually.

Share air / Give me your regulator. After the out-of-air signal, point to your mouth and then to your buddy's alternate (yellow octopus). The buddy hands over the alternate air source, both divers grip onto each other (typically by holding onto each other's BCD or shoulder), and the pair begins a slow controlled ascent.

I don't feel well. Point your fingers toward yourself and draw a large oval in front of your head and torso. This signal was officially added to PADI courses in 2023 to address a real gap — divers feeling sick (nausea, dizziness, faintness) previously had no clean way to communicate it without escalating to full emergency signals. Now you do. If you make it, your guide will assess and decide whether to slow down, ascend, or abort. Don't be shy about using it.

Danger / Hazard. Closed fist held upright, then pointing at the source of the danger. Used to flag an environmental hazard — strong current, an aggressive animal, a fishing line, a sharp obstacle. Not the same as a personal medical problem; this is about something in the environment.

How much air do you have? Point to your wrist or your air gauge with a questioning shrug. Sometimes formed by making a number signal in front of the chest. Your guide will ask this several times during the dive to make sure you're managing your gas correctly. You respond by holding up fingers to indicate the remaining pressure.

Number signals for pressure. There's no single universal system here, which is why guides usually establish the system at the briefing. The most common approaches: hold up one finger per 500 PSI (so seven fingers means 3500 PSI / about 240 bar), or for metric divers, use clear finger counts for bar (e.g. all five fingers shown twice followed by one finger for 110 bar). The simplest and most foolproof for many guides is to just have you hold the gauge up and show them — they'll read the number directly.

Low on air. Closed fist pressed against the chest. Made when you've hit your turnaround pressure — usually 100 bar or 1500 PSI for the start of the return swim, depending on the dive plan. This is a planning signal, not an emergency; the guide adjusts the dive to start heading back.

Stop / Hold. Flat hand held up, palm facing forward, like a traffic cop. Used to halt the group's movement — often to point something out, regroup, or wait for a slower diver. Easy to miss in low visibility, so guides often combine it with a light tap on the tank to get attention.

Direction (go that way). Hand flat, fingers together, pointing in the direction of travel. The most common gesture during navigation portions of a dive. Simple and unambiguous.

Stay together. Two index fingers held side by side, then pressed together. Used by guides when divers are spreading out too far. Buddy pairs use it to confirm they need to keep close.

Slow down. Hand flat, palm down, moved slowly up and down. Used when the group is descending too fast, ascending too fast, or moving too aggressively along the bottom.

Level off / Stay at this depth. Hand flat, palm down, held still at the diver's chest. Used when the group has reached the target depth and shouldn't go deeper. Important for managing nitrogen exposure and gas consumption.

I need to clear my ears. Point at your ear. Most guides will pause the descent for you to equalize. If you're really struggling, signal the "something is wrong" gesture first and then point to your ear.

I'm cold. Arms crossed over your chest, hands gripping opposite shoulders, the universal "cold" gesture from land. Tells the guide you may want to end the dive sooner than planned, especially on longer dives in cooler water.

My mask is leaking / I need to clear my mask. Point at your mask, sometimes followed by a quick demonstration of pulling water out. Most divers handle minor mask floods on their own, but if it's becoming a problem, this lets the guide know.

Pointing at a fish is the most common signal of all, but specific marine life signals exist for the more notable species. These vary slightly by region and guide, and most are intuitive imitations of the animal's shape or behavior. A few of the universal ones: shark — flat hand held to your forehead like a dorsal fin. Turtle — one hand laid flat on top of the other with thumbs out like flippers, gentle paddling motion. Eel or moray — fingers and thumb opened and closed to mimic the snapping jaw. Octopus — fingers wriggling downward. Ray or stingray — hand flat, fingers together, undulating side to side like wings. Barracuda — index finger and thumb pinched along a horizontal line, mimicking the long jaw.

More obscure species often get made-up signals — your guide may invent gestures during the dive briefing for whatever they expect to encounter. The point isn't to follow a rigid system; it's to communicate. When in doubt, just point and look excited.

Thumbs-up to mean "great!" Discussed above but worth repeating because it's the most frequent confusion. Thumbs-up underwater means "end the dive." If you want to express enthusiasm, use the OK circle, or stick to a simple nod or wide-eyed face.

Not responding to OK queries. Guides ask "OK?" frequently, especially with newer divers. Always respond with OK back, even if you're just casually swimming. A non-response prompts the guide to assume something is wrong and come check on you.

Signaling too small. Underwater visibility, mask field of view, and the slight blur of water all make small gestures hard to see. Make signals deliberately large and slow. A tiny OK signal made at chest level is easy to miss; a big OK signal held up in front of the guide's mask is unmistakable.

Hand signals only work if your buddy is looking at you. Underwater, divers often face the same direction watching the reef and miss visual signals from behind. There are three standard ways to get someone's attention.

Tank tapping. Most dive guides carry a small metal pointer, a tank banger (a rubber band with a hard plastic ball), or a piece of metal they can rap against the side of their tank. The sharp metallic sound travels well underwater and gets attention quickly. If you don't have a banger, knocking your dive knife handle, your dive light body, or even a fingertip ring against your own tank works in a pinch. Tap two or three short knocks rather than continuous banging — continuous noise usually means "emergency" and may panic divers around you.

Reef-friendly rattles and shakers. Some divers carry a small plastic tube with metal beads inside — shake it and the rattle carries 5 to 10 metres in clear water. Less ecologically problematic than tank banging in environments where the noise might disturb marine life. Useful on night dives or in murky water where visual signals fail.

Touch contact. If your buddy is close enough, a light tap on the shoulder, calf, or tank works. Always tap, don't grab — grabbing can startle a diver and trigger the wrong response. Approach from where they can see you peripherally if possible rather than from behind.

If you lose visual contact with your buddy during a dive, the standard procedure across every major training agency is the same: look around for one minute, then surface slowly. The one-minute search includes a 360-degree visual sweep in the immediate area, looking up to check the surface above you, looking down at the bottom, and listening for tank-banging or shaking sounds. If you can't see your buddy after one minute, you both meet at the surface, regroup, and either re-descend together or end the dive.

This procedure is reviewed in every dive briefing for a reason. Spending five or ten minutes searching at depth burns through air supply, increases nitrogen loading, and rarely succeeds — underwater visibility shrinks fast once you've lost sight of someone. Coming up early is far safer than searching too long. The lost buddy hand signal itself (rare to use because by definition the buddy who's lost can't see it) is two fingers held up vertically, indicating "I'm looking for you."

On night dives, hand gestures are largely replaced by light signals because nobody can see hands more than a metre or two away. Three patterns dominate. A slow vertical sweep of the light up and down means "I'm OK" or "are you OK?" — used the same way the OK hand signal is during day dives. A rapid back-and-forth horizontal wave means "something is wrong, look at me." And a slow circle traced with the beam means "come here." Most operators run through these on the night dive briefing because the patterns vary slightly between regions and agencies. Never shine your light directly into another diver's eyes — bright light underwater wrecks night vision instantly, and you'll need it for the rest of the dive.

The easiest way to internalize hand signals is to practice them on land before your trip. Stand in front of a mirror or with a partner and run through the core set: OK as a question and answer, up, down, problem (rocking hand), out of air (throat cut), share air (point to mouth then to alternate), I don't feel well (oval in front of body), low on air (fist to chest), and any marine life signals you're likely to use. Five minutes of practice a few times a week for two weeks before your trip is enough to make every signal automatic when you need it underwater. Most divers who struggle with signals during real dives simply haven't drilled them recently — it's a muscle memory skill, not a memorization one.

If you're taking your Open Water certification, hand signals are part of the course curriculum and you'll practice them in the pool and on early dives. If you're doing a Discover Scuba dive, your instructor will cover the basic safety signals (OK, up, down, problem, out of air) during the surface briefing — that's enough for that level of dive. Either way, reviewing the signals in this guide before you arrive gives you a head start, and means your in-water time gets spent on diving rather than learning to communicate. Reach out on WhatsApp if you have specific signal questions before your booking.