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Important Scuba Hand Signals to communicate underwater.

whale shark scuba hand signal

You are a scuba diver or want to become one? One of the most important things you are going to learn is how to communicate underwater with scuba hand signals.

Some of these diving hand signals are important to speak to your buddy and make sure you can sort out any problems that may arise. Others are a great way to communicate if you see a cool fish or marine creature during your dive.

whale shark scuba hand signal

While you will learn the most common scuba signals during your Open Water Course or a Discover Scuba Diving, it is a good idea to review them frequently especially if you dive with a new buddy. Most signals are universal but depending on where you dive or with whom they can vary a bit so it is a good idea to agree upon signals before you get in the water.

Click through to learn all about the Open Water Certification.

Throughout the dive, you need to make sure to stay close enough to your buddy so you can clearly signal to each other and see their response.

Which ones are the most important scuba diving hand signals? You can check them out here!

Scuba hand signals for safe diving

okay scuba hand signal

This is probably the most important scuba hand signal and is constantly used during a dive. The same sign for okay is used as both, a question and an answer. 
You will usually signal okay before descending as well as during the descent and once you reach your bottom depth. It is a good idea to check in with your buddy throughout the dive to make sure they are okay and definitely ask them if you see them struggling with anything or if conditions get a bit rough.  

scuba hand signal for problem

When you are asking your buddy if they are okay obviously, the desired answer is okay but sometimes it isn’t and that’s when the sign problem comes into play. Once you have signaled that there is a problem point towards whatever troubles you. i.e. to your ears if you can’t equalize, to your mask if it is fogged or keeps on flooding, to your leg if you have a cramp. This way your buddy can either assist you in sorting the issue out or at least wait for you to fix it. 

Up/ Down
up scuba hand signal

The signs for up and down are both used during descending and to signal the ascend as well as underwater if you want your buddy to come to your level. Important to remember – in diving a thumbs-up means up and not okay

Stop/ Slow down
stop scuba hand signal

This is a good one to remember if you can see someone is either getting a bit panicked or simply swimming too fast, exhausting themselves, or missing cool things to see.

Danger/ Abort dive
scuba hand signal for abort dive

This is generally the sign for danger or to abort a dive.

Out of air
scuba hand signal out of air

I will admit the sign for out of air is a bit of a morbid one, but keep in mind this is the sign for when things are really quite iffy. When you see your buddy making this sign, immediately grab your alternate air source and prepare to share your air. 

How much air?
scuba hand signal for how much air

This is an important one so it doesn’t come to an out of air scenario. You will see a lot from your instructor or dive guide but is also something you and your buddy can ask each other to make sure you know how much air the other person has. 

scuba hand signal for air in tank

The signs for air can vary throughout the world and will also vary depending on whether you are measuring your air in bar or PSI. 

For bar, a commonly accepted sign for 100 bar is a T/shape with your hands indicating that you have half a tank left (most tanks start with 200 bar). For each additional 10 bar you hold up one of your fingers – again, thumbs-up doesn’t count here! 
If you are getting to 50 bar which means low on air, you will most likely put a fist on your shoulder. When in doubt, discuss beforehand with your buddy or dive crew what signs you can all agree on. 

scuba hand signal for breathe

This often goes hand in hand with slow down and is simply a reminder to inhale and exhale calmly. 

Buddy up
scuba hand signal for buddy up

This is a sign you will see from your instructor or dive guide implying that you should stay closer to your buddy


This indicates that you are swimming into a current and usually implies that you may want to turn around if possible.

I’m cold
scuba hand signal for cold

I guess this a signal that works above and below the surface and one you will see me do quite frequently.

scuba hand signal for boat

This is a useful little sign to either show that you can see your boat or are starting to head back to the boat. 

Safety stop
scuba hand signal for safety stop

This sign indicates that it is time for a 3 minutes safety stop (shown by holding up 3 fingers), usually done at 5 m depth (shown by 5 fingers on top). 

Scuba hand signals for fish & marine life

Especially if you are a fairly new diver you will be excited about pretty much anything and everything you see underwater. And while it is a great idea to have a fish ID book or slates at hand for after the dive, knowing a few signs to identify marine life while diving is a good idea.

From my experience, fish signals can differ quite a bit depending on where you dive so it is a good idea to check with your dive guide beforehand if there is anything special to look out for and how to signal for it.

turtle scuba hand signal

squid scuba hand signal

scuba hand signal for octopus

Frog fish

Leaf fish
scuba hand signal for leaffish

scuba hand signal for boxfish

tuna scuba hand signal

Yup, this shows opening a can of tuna – I know it is a bit of a morbid one…

scuba hand signal for barracuda

You are indicating the stripes of a barracuda.


To be honest, I am not sure if that is an official signal but we did a lot of air guitar playing when we saw a guitar shark in Mauritius.

trigger fish scuba hand signal

scuba hand signal for lionfish

Moray eel
scuba hand signal for moray eel

scuba hand signal for nudibranch


Bullshark or Lobster
scuba hand signal for bullshark

I have seen this sign used for bull sharks in South Africa, however, it is also used for lobsters – I guess you would know beforehand which of the two you are more likely to see. 

shark scuba hand signal

The open mouth may happen but is probably not advisable underwater.


If someone pretends to be Princess Leia you might get lucky and see a hammerhead.


To be honest, I am not sure if that is an official signal but we did a lot of air guitar playing when we saw a guitar shark in Mauritius.

whale shark scuba hand signal

I am not sure how many people actually use this – chances are if there is a whale shark close by you will hear someone scream with excitement.

Obviously, there are quite a few more scuba hand signals and I have just shown you some of my favorites. Again check with your buddy or dive guide before getting in the water what you may see during your dive and how to signal for it.

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