20 Common Scuba Diving Hand Signals

Oceania, Micronesia, Yap, Diver with grey reef sharks, Carcharhinus amblyrhynchos
Westend61 / Getty Images

When you're scuba diving with friends and you need to communicate underwater, knowing these 20 common scuba diving hand signals can really come in handy and, more importantly, keep you safe. It's a very important second language for anyone who dives. Many of these hand signals are similar to common gestures and are easy to learn.

01
of 20

'OK'

Photo of a diver communicating "okay" underwater.
Natalie L Gibb

The first-hand signal that most scuba divers learn is the "OK" hand signal. Join the thumb and index fingers to form a loop and extend the third, fourth, and fifth fingers. This signal can be used as both a question and a response. The "OK" sign is a demand-response signal, meaning that if one diver asks another diver if he is OK, he must respond with either an "OK" signal in return or with the communication that something is wrong. The "OK" hand signal should not be confused with the thumbs-up signal, which in scuba diving means "end the dive."

02
of 20

'Not OK' or 'Problem'

How to make the problem sign in scuba diving.
Natalie L Gibb

Scuba divers communicate a problem by extending a flattened hand and rotating it slowly side to side, similar to how many people signal "so-so" in a normal conversation. A diver communicating a problem underwater should then point to the source of the problem using his index finger. The most common use of the "problem" hand signal is to communicate an ear equalization problem. All student divers learn the "ear problem" sign before they enter the water for the first time. 

03
of 20

'OK' and 'Problem' on the Surface

How to communicate okay and problem in the surface when scuba diving.
Natalie L Gibb

During the open water course, scuba divers also learn how to communicate "OK" and "problem" on the surface. These surface communication signals involve the whole arm so that boat captains and surface support staff can easily understand a diver's communication from far away.

The "OK" sign is made by joining both arms in a ring above the head, or if only one arm is free, by touching the top of the head with the fingertips. To indicate a problem the diver waves his arm overhead to call for attention. Don't wave "hi" to a dive boat on the surface because the captain is likely to think you need assistance.

04
of 20

'Up' or 'End the Dive'

The "up" underwater communication for scuba diving.
Natalie L Gibb

A thumbs-up sign communicates "up" or "end the dive." The "up" signal is one of the most important signals in scuba diving. Any diver can end the dive at any point for any reason by using the "up" signal. This important dive safety rule ensures divers are not forced beyond their comfort level underwater. The "up" signal is a demand-response signal. A diver who signals "up" to a fellow diver should receive the "up" signal in return so that he can be sure that the signal was understood.

05
of 20

'Down'

The descend hand signal for scuba diving
Natalie L Gibb

The thumbs-down hand signal communicates "go down" or "descend" underwater. The "down" signal is used in the first step of the five-point descent, in which divers agree that they are prepared to begin to go deeper.

06
of 20

'Slow Down'

How to communicate slow down underwater
Natalie L Gibb

The "slow down" hand signal is another basic signal that all student divers learn before their first scuba dive. The hand is held out flat and motioned downward. Instructors use this signal to tell enthusiastic students to swim slowly and enjoy the incredible underwater world. Not only does swimming slowly make diving more fun, it also helps to avoid hyperventilation and other dangerous underwater behaviors.

07
of 20

'Stop'

How to communicate stop and hold underwater.
Natalie L Gibb

Divers typically communicate "stop" in one of two ways. The first method (common in recreational diving) is to hold up a flat hand, palm forward, as a traffic cop would.

Technical divers, however, favor the "hold" sign, made by extending a fist with the palm-side of the fist facing outward. The "hold" sign is a demand-response signal: A diver who signals "hold" should receive a "hold" sign in return, indicating that his fellow divers have understood the signal and agree to stop and hold their position.

08
of 20

'Look'

How to Communicate "Look at" underwater.
Natalie L Gibb

The "look" hand signal is made by pointing the index and third fingers at your eyes and then indicating the object to be observed. A scuba instructor uses the "look at me" signal to indicate that students should watch him demonstrate an underwater skill, such as ​mask clearing during the open water course. "Look at me" is signaled by making the "look" signal and then gesturing toward your chest with a finger or thumb.

Divers can also enjoy showing each other aquatic life and other underwater attractions by using the "look over there" signal, made by signaling "look" and then pointing toward the animal or object.

09
of 20

'Go in This Direction'

The "Go in This Direction" Hand Signal for Scuba Diving
Natalie L Gibb

To indicate or suggest a direction of travel, scuba divers use the fingertips of a flattened hand to point out the desired direction. Using all five fingers to point out a direction of travel helps to avoid confusion with the "look" signal, which is made by pointing with a single index finger.

10
of 20

'Come Here'

The Come Here Hand Signal for Scuba Diving
Natalie L Gibb

For the "come here" hand signal, extend a flattened hand, palm up, and bend the fingertips upward toward yourself. The "come here" signal is basically the same signal that people use in everyday conversation. 

11
of 20

'Level Off'

The Level Off hand signal for scuba diving.
Natalie L Gibb

The "level off" hand signal is used to tell a diver ​to remain at the current depth or maintain this depth. The "level off" signal is most commonly used to communicate that divers have reached the planned maximum depth for a dive or to tell divers to hold previously designated depth for a safety or decompression stop. For the "Level Off" signal, extend a flattened hand, palm down, and slowly moving it side to side horizontally.

12
of 20

'Buddy Up' or 'Stay Together'

The Buddy Up hand Signal for Scuba Diving
Natalie L Gibb

A diver places two index fingers side by side to indicate "buddy up" or "stay together." Scuba diving instructors use this hand signal to remind student divers to stay close to their diving partner. Divers also occasionally use this signal to reassign buddy teams underwater. For example, when two divers are low on air and ready to ascend, they can communicate that they will stay together and ascend using the "buddy up" hand signal.

13
of 20

'Safety Stop'

How to communicate "Safety Stop" underwater while diving.
Natalie L Gibb

The "safety stop" signal is made by holding the "level off" signal (a flat hand) over three raised fingers. A diver is indicating "level off" for three minutes (the minutes signified by the three fingers), which is the minimum recommended time for a safety stop.

The safety stop signal should be used on every dive to communicate within the dive team that the divers have reached the pre-determined safety stop depth and agree to maintain that depth for a minimum of three minutes.

14
of 20

'Deco' or 'Decompression'

The Decompression signal for scuba diving.
Natalie L Gibb

The "decompression" hand signal is commonly made in one of two ways—either with an extended pinkie or with an extended pinkie and thumb (similar to a "hang loose" sign). Technical divers trained in decompression diving techniques use this signal to communicate the need for a decompression stop. Recreational divers should also be familiar with this signal.

Although recreational scuba divers should never plan to make a decompression dive without proper training, this sign is useful in the unlikely event that a diver accidentally exceeds their no-decompression limit for a dive and must communicate the need for an emergency decompression stop.

15
of 20

'Low on Air'

The Low-On-Air hand signal for scuba diving.
Natalie L Gibb

For the "low on air" signal, place a closed fist against your chest. This hand signal is not used to indicate an emergency but to communicate that a diver has reached the predetermined tank pressure reserve for the dive. Once a diver communicates that she is low on air, she and her diving partner should agree to make a slow and controlled ascent to the surface and end the dive by using the "up" signal.

16
of 20

'Out of Air'

The Out of Air Hand Signal for Scuba Diving.
Natalie L Gibb

The "out of air" signal is taught to all open water course and experience course students so that they know how to react in the unlikely event of an out-of-air emergency. The chances of an out-of-air emergency when scuba diving are extremely low when proper pre-dive checks and diving procedures are observed.

To make this signal, move a flat hand across your throat in a slicing motion to indicate that the air supply is cut off. This signal requires an immediate response from the diver's buddy, who should allow the out-of-air diver to breathe from his alternate air-source regulator while the two divers ascend together.

17
of 20

'I'm Cold'

The "I'm Cold" hand signal for scuba diving.
Natalie L Gibb

A diver makes the "I'm cold" signal by crossing his arms and rubbing his upper arms with his hands as though he is trying to warm himself.

This hand signal is not frivolous. If a diver becomes excessively chilled underwater, he could lose reasoning and motor skills. Plus his her body will not eliminate absorbed nitrogen efficiently. For these reasons, it is imperative that a diver who begins to feel excessively chilled communicate the problem using the "I'm cold" signal, end the dive, and begin his ascent to the surface with his dive buddy.

18
of 20

'Bubbles' or 'Leak'

How to communicate "bubbles" or "leak" underwater.
Natalie L Gibb

The "bubbles" or "leak" signal communicates that a diver has noticed a leaking seal or bubbling piece of gear either on herself or her buddy. To make the "bubbles" hand signal, open and close your fingertips rapidly. You should then end the dive and begin a slow and controlled ascent to the surface.

19
of 20

'Question'

The "Question" hand signal for scuba diving.
Natalie L Gibb

For the "question" signal, raise a crooked index finger to mimic a question mark. The "question" signal is used in conjunction with any one of the other scuba diving hand signals. For example, the "question" signal followed by the "up" signal communicates "Should we go up?" and the "question" signal followed by the "cold" signal could be used to express "Are you cold?"

20
of 20

'Write It Down'

The hand signal for "Write It Down" when scuba diving.
Natalie L Gibb

When all other communication fails, divers sometimes find it easiest to simply write down the information to be communicated on an underwater slate or wet-notes underwater notebook. A writing device is a valuable tool underwater. It can save time and increase diver safety by allowing a diver to express complex ideas or problems. The "write it down" signal is made by pantomiming that one hand is a writing surface, and the other hand is writing with a pencil.