Dive Buddy Communication: Hand Signals and Protocols

Why Standardisation Matters

Underwater communication is entirely non-verbal: gestures, lights, slates, and occasional touch are the tools. The problem is that hand signals are not truly standardised across certification agencies or regions — an 'OK' signal that means 'everything is fine' in PADI-trained divers may look like 'surface' to SSI-trained divers in some countries. The solution is not to memorise all variants but to ensure that every buddy team agrees on signals before every dive.

Core Signals Every Diver Knows

The baseline signals that are consistent across nearly all certification systems:

OK (at depth): Thumb and forefinger making an O with the remaining three fingers extended. Signalled and returned — always wait for confirmation.

OK (at surface): Both arms extended overhead to form a ring — this is the surface-visible version when the hand signal is not visible from a boat at distance.

Problem / Something Is Wrong: Flat hand, palm down, rocking side to side (like a tipping scales). This initiates a check — the buddy responds by looking and asking where the problem is.

Out of Air: One hand cutting horizontally across the throat repeatedly.

Share Air / I Need Your Alternate: Same cutting motion, then pointing to mouth.

Ascend: Thumb pointing upward.

Descend: Thumb pointing downward.

Stop / Hold: Open palm facing the buddy.

Come Here: Beckoning motion with one or more fingers.

Look at That: Two fingers of one hand pointing at the eyes, then redirected at the subject.

How Much Air? One hand, five fingers spread, touching the side of the head (like a gauge at the ear).

Low Air (50 bar): Closed fist.

Reserve (50 bar) / Turn the Dive: Fist repeated emphatically or touching the top of the head with an open hand.

Night Diving Signals (Light-Based)

At night, hand signals become invisible. Light signals replace them:

• Slow wide circle with torch beam: OK
• Rapid small circles: Emergency / get attention
• Wide slow arc up and down: I am at the surface / distress (visible to boats)
• Point beam at subject, then at buddy's eyes: Look at this

Never shine a torch directly into another diver's face — it destroys their night vision for several minutes.

Pre-Dive Briefings

The most valuable communication happens before the dive. A good pre-dive briefing between buddies covers:

1. Maximum depth: Agreed maximum for the dive — both state it, both agree
2. Turn pressure: The pressure at which you start returning (typically one third or the agreed bar)
3. Minimum surface pressure: The air pressure at which you will signal to surface regardless of dive time
4. Separation protocol: If separated, spend one minute at depth searching, then both surface slowly and reunite above
5. Emergency action: Where the nearest O₂ kit is, where the nearest chamber is, how to contact DAN
6. Specific hand signals for the dive: If you plan a night dive, agree on torch signals; if diving a new site, agree on how to communicate site-specific navigation

Slates and Wrist Boards

For more complex communication — marine life identification, photographic subject confirmation, directions in a wreck — an underwater slate (a small white board with a pencil on a lanyard) or a wrist board allows written notes. Useful tools for:

• Dive guides communicating species names to guests
• Photographers directing a buddy to a subject's position on a complex wreck
• Navigation notes when diving a complex site for the first time

Wrist-mounted computer screens with basic text messaging are available in some advanced dive computers, though they are expensive and primarily used in technical diving.

Buoyancy Signals in Current

In drift diving, where visual contact may be intermittent, physical contact becomes important. In low visibility or strong current:

• A sustained squeeze of the buddy's hand means 'OK' (squeeze back to confirm)
• A rapid repeated squeeze means 'problem' or 'stop'
• Tapping a buddy's tank with a pointer is a common attention signal in zero-visibility conditions