Light Signals for Dive Teams

Dive teams use three basic light signals. A slow circle on the bottom or a wall in front of a teammate means OK. A slow side-to-side or up-and-down sweep means attention. A rapid back-and-forth movement means emergency. OK and emergency signals always need a response, and you never shine your light into a teammate's eyes.

By Jeremiah Gardner · Last reviewed October 16, 2026

A light is the fastest way to talk underwater. A teammate can see a beam out of the corner of their eye long before they'd notice a hand signal, and in low visibility or at night, it may be the only thing they see.

Teams that dive with lights use a small set of signals and a few habits that keep the beam useful instead of blinding.

What are the basic light signals?

Signal	Light movement	Meaning	Response
OK	A slow circle on the bottom or a wall in front of your teammate	"I'm OK. Are you OK?"	Circle back to confirm
Attention	A slow, steady sweep, side to side or up and down	"Look at me" or "look at this"	Turn toward the light
Emergency	A rapid, repeated back-and-forth movement	"I have a problem, now"	Go to the diver immediately

These conventions come from cave diving, where lights are the main way teams communicate. They're widely used by DIR and technical divers in open water too. Agree on them in your pre-dive briefing, because small variations exist between teams and agencies.

Two of the three signals are questions. An OK circle always needs an OK circle back, and an emergency signal always needs an immediate response. If a teammate doesn't answer, treat it as a problem until you know it isn't.

How do you use a light without blinding people?

Never point your beam into a teammate's face. Aim at the bottom or a wall in front of them.
Light up your own hand to sign. Point the light back at your hand so your teammate sees the signal lit from their side.
Keep your beam where the team can see it. A steady beam pointed slightly ahead tells everyone where you are without anyone having to look for you.
Move it deliberately. A beam waving around while you swim can look like an attention or emergency signal.

The third habit is the one experienced teams rely on most. When everyone's light is in view, a teammate who stops, turns or drops back is obvious instantly.

What hand signals should a team agree on?

Lights get attention; hands carry the details. Agree on these before the dive and make sure everyone uses the same version:

OK and problem
Up, down, stop and hold
Out of gas: the signal for an immediate gas share
Low on gas and turn the dive
Pressure check: each diver shows their remaining gas
Something is wrong with my equipment, followed by pointing to it

In zero visibility, teams switch to touch contact: a hand on a teammate's arm or shoulder, with a few agreed squeezes or taps for messages like OK and stop.

Why carry a primary light on daytime dives?

Because communication doesn't stop being useful in daylight. Even in 20 feet of visibility, a beam on the sand is easier to notice than a hand, and it lets a team stay in contact while looking around.

UTD's minimum equipment for its open-circuit classes includes a primary light and a backup light, with two backups for overhead diving. The open water course is the exception. The backup clips to a chest D-ring, so if the primary fails, you can deploy it and keep communicating.

Light discipline in practice

Check in often. A quick circle every few minutes keeps the team connected.
Answer every question signal. Even when you're busy.
Lead with the light, then sign. Get attention first, then show the hand signal.
Practice on easy dives. Signals become automatic only by using them when nothing is wrong.

Learn it as part of the team

Communication, team positioning and light use are part of Essentials of Recreational Diving. For how signals fit into the rest of team diving, read Team Diving vs Buddy Diving.

Frequently asked questions

Do I need a light on a daytime dive?

A primary light makes communication easier in any visibility, and UTD's minimum equipment for most open-circuit classes includes a primary light and a backup. It's how a team signals across a few feet of murky water.

How do I show a hand signal at night?

Point your light at your own hand, not at your teammate. Hold the light so it illuminates the signal from their point of view.

What if my teammate doesn't answer an OK signal?

Treat it as a possible problem. Repeat the signal, move closer and check on them. Every question signal needs an answer.

What should I do if my primary light fails?

Deploy the backup, signal the team and establish the exit response. If light is required for the dive, a primary failure is a critical event; a backup does not justify continuing the original objective. A light failure is one reason divers carry a backup clipped to a chest D-ring.