Scuba Diving Hand Signals: The Essential Guide
by Yannick Schroth
Jul 29, 2026
7 min read
Photo: Dajana Reçi via Pexels (free licence).
This is a general reference, not a substitute for training and the pre-dive briefing.
The critical few
- OK = thumb-and-forefinger circle (NOT thumbs up).
- Thumb up = go up / end the dive; thumb down = descend.
- Out of air = flat hand across the throat.
- Low on air = fist to the chest.
- Distress at the surface is its own signal: wave one arm from horizontal to overhead.
- Always confirm signals in the briefing; the standard itself tells you to.
Why hand signals matter
Underwater you cannot speak, so hand signals are how divers stay coordinated and safe. They let you confirm you are OK, agree to go up or down, share how much air you have, point out hazards or marine life, and, crucially, communicate an emergency like being out of air. A diver who knows the signals cold and watches their buddy is a safe buddy.
The essential signals
| Signal | How | Meaning |
|---|---|---|
| OK? | Thumb and forefinger in a circle, the three remaining fingers extended if you can (in thick gloves or mittens you often cannot) | "Are you OK?" and, returned, "OK!" |
| OK (distance or surface) | Both arms overhead, fingertips touching, making a large O. One arm to the top of the head if the other hand is busy | OK from far away or at the surface |
| Something is wrong | Hand flat, palm down, fingers apart, thumb out, rocked back and forth on the axis of the forearm | "Something is wrong", then a second signal for the source |
| Distress, help me | Wave the hand quickly from horizontal to overhead, striking the water's surface on the way | Emergency at the surface, and a different signal from "something is wrong" |
| Up / end dive | Fist, thumb extended upward, moved upward | "Go up" or "I'm going up" |
| Down / descend | Fist, thumb extended downward, moved downward | "Go down" or "I'm going down" |
| Stop | Hand raised vertically, fingers together, palm facing the receiver | "Stop", usually followed by the reason |
| Low on air | Clenched fist moved inward toward the chest, repeated for urgency | "I'm low on air" |
| Out of air | Hand flat, fingers together, palm down, drawn across the throat in a cutting motion | Emergency: "I'm out of air" |
| Let's share air | Point at your regulator with the fingers of the left hand, or take the regulator out and point to your mouth | "Share air with me", the signal that follows out of air |
| Danger | Clenched fist with the arm extended toward the danger, or both fists crossed in front of the body | "Danger there". Note that a fist is danger, not stop |
| Level off | Hand flat, palm down, fingers apart, moved slowly back and forth horizontally | "Level off at this depth" |
| Watch or look | Tips of the forefinger and middle finger against the mask lens | "Look", then a signal for where or whom |
| Come here | Sweep the hand toward the body in a beckoning motion | "Come to me" |
| Get with your buddy | Both hands in fists, forefingers extended, brought together | "Stay close" |
| Which direction? | Fist with thumb extended, rotated through 180 degrees several times | "Which way?" To answer, point with the extended thumb: that is "go that way" |
| Ears not clearing | Point to one ear with the forefinger | "I can't equalise" |
| I am cold | Arms crossed in front of the chest, hands gripping the upper arms | "I'm getting cold" |
| Take it easy | Hand flat, palm down, flexed slowly up and down | "Slow down" |
Signalling your air
Sharing how much air you have left is vital, and the convention varies. Some divers show numbers with their hands for the remaining pressure; others rely on the low on air (fist to chest) and out of air (hand across throat) signals for the critical states. Because number conventions differ between regions and operators, confirm the local method in the briefing. Check your gauge often and signal early, never wait until you are nearly empty.
Beyond hand signals
Signals are the main tool, but not the only one. Divers also use a slate or wet notes to write messages, a torch to signal or point (especially on night dives), and tank taps or noise-makers to get attention. Agree how you will get each other's attention before the dive.
The golden rule: agree signals first
The core safety signals are broadly standard, but marine-life signals, air-number conventions and regional customs vary. That is why every good dive briefing reviews the signals, and why you should always confirm them with your buddy and guide before each dive, especially somewhere new. A signal only works if both of you mean the same thing by it.
FAQ: scuba hand signals
What are the most important scuba hand signals?
The essentials are: OK (thumb and forefinger in a circle), a problem or not okay (flat hand rocked side to side), up or end the dive (thumb up), down or descend (thumb down), stop (flat palm held up), out of air (a flat hand drawn across the throat), and low on air (a fist to the chest). These cover safety and direction. Learn and practise them until they are instant, and always confirm them with your buddy and guide before the dive.
Does the thumbs up signal mean okay in scuba diving?
No, and this is a critical point. Underwater, thumbs up means go up or end the dive, not okay. To say okay you make a circle with your thumb and forefinger. Confusing the two can end a dive early or, worse, cause a misunderstanding in a real situation, so make sure everyone in your group knows that OK is the circle and thumb up means ascend.
How do you communicate underwater when scuba diving?
Mostly with standardised hand signals, since you cannot speak. Divers signal things like OK, up, down, out of air, low on air, stop, direction, look here, and how much air they have left. You can also use a slate or wet notes to write, and some divers use torch or tank-tapping signals to get attention. The key is that both divers understand the same signals, so agree them before you get in.
Are scuba hand signals the same everywhere?
Largely, and there is a document behind that. The Recreational Scuba Training Council published Common Hand Signals for Recreational Scuba Diving, effective 1 December 2005, as minimum course content for its member agencies IDEA, PADI, PDIC, SDI and SSI, so the core set of OK, up, down, stop, low on air and out of air is genuinely standardised across most of the recreational world. Agencies outside that membership are not bound by it, and the standard itself notes that natural and local signals sit alongside the ones it defines, which is why marine-life signals and air-number conventions still vary. The standard's own advice is to review signals before every dive.
How do you signal how much air you have left?
There are a few conventions, so confirm the local one in the briefing. Divers often signal remaining pressure using numbers with their hands (for example showing digits for hundreds of a pressure unit), or use the low on air signal (a fist to the chest) and out of air signal (hand across the throat) for the critical states. Because number conventions vary, agreeing them before the dive is essential.
Yannick Schroth
Founder of NOMADREEF and a former digital nomad. This is a general reference to common recreational dive signals; signals vary by agency and region, so always follow your training and the pre-dive briefing. About the author · LinkedIn ↗
Sources
- Recreational Scuba Training Council, "Minimum Course Content for Common Hand Signals for Scuba Diving", effective 1 December 2005. Every signal in the table above is taken from this document, in its own words: stop as "raise hand vertically, fingers together, palm facing the receiver"; distress as "wave hand quickly from a horizontal position to a position overhead"; out of air as a flat hand "across the throat in a cutting motion"; danger as "a clenched fist with one hand and extend arm in the direction of danger". Its purpose line is "to formally standardize the most common hand signals used during recreational scuba diving", its members are listed in Appendix A as IDEA, PADI, PDIC, SDI and SSI, and it instructs that "regardless of the experience and knowledge of the divers involved, it is always prudent to review hand signals and their meanings prior to each dive". RSTC standard (PDF), checked 12 August 2026. Corrected 12 August 2026: an earlier version of this page stated that "no body publishes one binding list for recreational diving". That was wrong, and this document is the counter-example. Three signal descriptions were corrected with it: stop was given as "flat palm held up (or a fist)", but a fist is danger in the standard; "which way" was described as a tilted flat hand rather than the rotated thumb; and "look" was given as pointing to your eyes rather than the fingertips to the mask lens. Distress at the surface, share air, danger, ears not clearing, cold and take-it-easy were missing from the table entirely, and two of those are emergency signals.
- What the standard does not settle. It distinguishes natural, local and special signals and defines only the third group, so a cupped hand for abalone or a local marine-life vocabulary sits outside it. Agencies that are not RSTC members, among them NAUI, RAID, CMAS and BSAC, are not parties to the document, and agency course materials are revised over time, so the standard you were certified under governs, not this article.
- General information for certified divers. It is not training, and no article replaces a course, a briefing or a competent guide.