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.
- Always confirm signals in the briefing; some vary by operator and region.
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 | "Are you OK?" / "I'm OK" (up close) |
| OK (distance) | Arm on head or both arms in a circle overhead | OK from far away or at the surface |
| Problem / not OK | Flat hand rocked side to side | "Something is not right" (then point to what) |
| Up / end dive | Thumb up | "Let's ascend / end the dive" |
| Down / descend | Thumb down | "Let's go down" |
| Stop | Flat palm held up (or a fist) | "Stop / hold here" |
| Low on air | Fist to the chest | "I'm getting low on air" |
| Out of air | Flat hand drawn across the throat | Emergency: "I'm out of air" |
| Level off | Flat hand, palm down, moved horizontally | "Stay at this depth" |
| Look / watch | Point to your eyes, then to the thing | "Look at that" |
| Come here | Beckon with the hand | "Come to me" |
| Buddy up / stay together | Two fingers together, or point between you | "Stay close" |
| Which way? | Flat hand tilted, or point | "Which direction?" |
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?
The core safety signals (OK, up, down, out of air, low on air, stop) are broadly standard across agencies and countries, but some signals, especially for specific marine life, air pressure numbers, or regional customs, vary between operators and regions. That is exactly why every good dive briefing reviews the signals, and why you should confirm them with your buddy and guide before each dive, especially somewhere new.
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
- Training-agency standards (PADI, SSI, RAID and equivalents) for course content, signal sets and speciality prerequisites. These differ between agencies and 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.