Scuba diving, just like any activity with a certain level of risk, has many do’s and don’ts. You learn about most of them in your dive training. But it seems that the more experienced divers get, the more they tend to think the rules don’t apply to them anymore. It’s exactly for this reason, that most fatal diving accidents happen to experienced divers, and not to newbies.

Then there are the rules in between the lines: they are not discussed in diver training, so you have to learn them along the way. This list is a combination of things divers tend to ‘forget’ about as their experience grows, and things that may not be so obvious to every diver. Nonetheless, here are 10 things you should never do in scuba diving:

1. Touch marine life

This one is imprinted in divers early on in scuba training, but it always surprises me how many divers (choose to) forget about this essential rule, as soon as a turtle or whale shark comes within arms reach. Not touching marine life has two beneficiaries: the marine life itself and yourself. 

One thing you should always remember is that we are a guest in the underwater world. We don’t belong there – our presence alone disturbs marine life enough as it is. On top of that, the acidity of our skin can be toxic to marine animals. And even if it doesn’t hurt or kill them, just imagine the unnecessary stress you’re causing another living creature.

Even if you don’t care about all of that (you’re a bad person tbh): many marine animals are venomous to us too. I once guided a diver who decided to touch a lionfish. He freaked out as his whole hand started to swell. We had to end the dive for the whole group because this one diver required medical attention. Nothing serious happened, but you can imagine his fellow divers were not happy.

Things You Should Never Do In Scuba Diving: Touch Marine Life
No, this turtle really does NOT want to be touched by you

2. Use a pointer stick

Saying this will probably not make me very popular, because I know there are many pointer stick lovers out there. But it’s something I truly believe in since I’ve seen many – if not most – divers out there abusing pointer sticks. I guess there are two exceptions to this rule: divemasters who regularly point out miniscule marine life, and photographers who use a pointer stick as a reference tool when taking photos. ANYONE ELSE DOES NOT NEED A POINTER STICK.

Let me explain why I’m so against them: they make divers lazy. People use them to compensate for a lack of dive skills. Or just because it takes less effort than actually using those dive skills. How tempting is it to just use a pointer stick to keep your distance from marine life? Or to help maintain your buoyancy? It’s extremely tempting, I also do it if I carry one with me. But the thing is: touching something with a piece of metal is still touching. You just don’t use your own skin. It’s very simple: if you don’t have your buoyancy under control, or if you don’t know how to fin backwards, then don’t get too close. Take an extra dive course and practice. But if you use a pointer stick to compensate for your lack of dive skills you will never ever learn.

There’s so much more I want to say about this topic, so I’ll dedicate a full blog post about it soon 🙂

3. Dive without a DSMB

Why dive training organizations don’t emphasize the importance of a DSMB (delayed surface marker buoy) is beyond me. It’s a mandatory piece of equipment for divemasters and instructors, but not for individual divers. In my opinion, it should be. For those who need a refresher: a DSMB is a balloon shaped like a sausage, that you let up to the surface before ascending to let people know you’re there. It’s especially important in an area with heavy boat traffic or strong currents. As mentioned your dive pro should always carry one. 

But what if you get seperated from the group for whatever reason? If that happens, the first step you need to take is making a safe ascent by yourself. In an area with many boats, ascending without a DSMB is very risky. The second step is making sure people (the other divers or the boat crew) can see you once you’re at the surface. if you’ve drifted off very far, that will be very difficult, especially if it’s choppy. Having a DSMB to get their attention may save your life in this scenario. It’s such a cheap piece of equipment too, so it’s really a no-brainer to me.

4. The quarter turn back

The quarter turn back is performed when a diver opens a tank, then slightly closes it again (a quarter turn). The idea behind this is that a tank valve can be damaged when opening it all the way, and the quarter turn back should prevent this. For many years, this was the way divers learned to set up their equipment. However, most training agencies are not recommending this method anymore.

The reason for that is that it can cause a lot of unnecessary confusion. How much is a quarter turn back? It’s an easy mistake to close it too far. Another common scenario is that if another diver (or boat crew) checks if your air is open, accidentally turns it off (really, it happens!) – and then a quarter turn open

Entering the water with a partially open tank is actually more dangerous than entering the water with a closed tank. If your tank is all the way closed, you will notice that immediately when descending. But if your tank is partially open, breathing on (or close to) the surface will feel fine. But when you reach depth, your air flow will be restricted due to pressure changes. There are several reports from all over the world where this has led to the drowning of divers – hence why training agencies have moved away from the quarter turn back.

Unfortunately I still see divers, boat crew and even instructors doing the quarter turn back all the time. It may seem like such a small thing, but to me this is one of the most important things you should never do in scuba diving!

5. Skip your pre dive safety check

We all know that this is one of the things we should never do in scuba diving. Yet it’s the number one example where experienced divers think they don’t need it anymore. I’m not talking about remembering the BWRAF acronym by heart. The acronym is just a tool to make sure you don’t forget any steps. If you can perform a thorough check without an acronym, that’s completely fine.

Here’s why the pre dive safety check is so important. If there’s something wrong with your equipment, you want to find out before you’re in the water. In case of a serious problem; a check may just save your life. In case of a small problem; it will prevent you from making a fool of yourself. It happens regularly that divers discover upon their descent that oops! – their tank is not open yet. Or that we have to end the dive early because oops! – the boat crew forgot to change their tank (damn you boat crew!) It causes a lot of delay, even more eye rolling, and is just really unnecessary. So just do the damn check.

Things You Should Never Do In Scuba Diving: Skip Your Pre-Dive Safety Check
If there’s something wrong with your equipment, you want to find out before entering the water

6. Compare yourself to other divers

Probably the most common question on a dive boat is “how many dives do you have?” The diver with the highest number automatically outranks all the others. Well, here’s another unpopular opinion: someone’s number of dives mean absolutely nothing. I’ve seen divers with 30 dives that had better skills than someone with 300 dives. Sometimes divers with thousands of dives have adopted many bad (careless) habits along the way, and because they are ‘so experienced’, they’re very hard to correct.

Another common question after a dive is “how much air do you have left?” The diver with the most air left in his tank gets the most respect. It’s true that air consumption and experience go hand in hand, but that’s not the only determining factor. Everybody is different and will consume air at a different pace. Besides, who cares? If you go to the gym you don’t compare how much air everyone is breathing to measure their fitness level. 

The reason why I don’t like this question is because people can feel really bad about being the first to be low on air. I once guided a diver who lied to me about the remaining air in his tank, because he was embarrassed about it in front of the group. He thought/hoped he still had enough air to make it back to the boat, which he didn’t. All ended well with me sharing my air with him, but it just shows how comparing your air consumption to others is not only silly, it can even lead to a dangerous situation.

7. Dive beyond your limits

Another rule that is widely discussed in entry level dive training, but very often ignored after that. Every dive certification has a depth limit. During the course your instructor makes sure you don’t pass that limit, but afterwards there is no scuba police that checks on you. It’s completely up to you if you stick to those limits or not. So who cares if you go to 18 meters or 20 meters, right? How about 25 meters? Or 30 meters?

The first reason why you shouldn’t go deeper than your training allows you is gas narcosis. The first time you go to a new depth limit should always be with an instructor, who knows what to do if gas narcosis occurs.

The second reason to stick to your depth limit is your (in)ability to handle problems at depth. Do you have the skills and confidence to deal with an emergency at 25 meters? You may be forgiven for panicking and shooting up to the surface from 18 meters deep, but if that happens at 25 or 30 meters, there’s a higher chance you’ll pay the price.

Diving within your limits doesn’t only apply to depth. It’s just as much about different (more risky) dive environments, such as currents, wrecks or diving at night. It’s all great fun as long as things go well, but can you handle yourself in an emergency in environments like these? If you did not get the required training, the answer is most likely no.

Things You Should Never Do In Scuba Diving: Dive Beyond Your Limits
Scuba diving is a relatively safe activity when done within the limits of your training

8. Put your mask on your forehead

New divers LOVE to put their mask on their forehead. As soon as their head breaks the surface – pop – that mask moves up. It’s one of the things that annoys instructors the most during a course. Let me start by saying that as long as you’re in the water, you should keep your mask on your face. Things can still go wrong on the surface (actually most scuba accidents happen on the surface). When they do, you really don’t want salt water in your eyes. But if you insist on taking off your mask immediately after surfacing, then at least hang it around your neck.

Here’s why: when you have your mask on your forehead, even the tiniest movement or wave can knock it off. You probably won’t believe me until it happens to you. But trust me when I say I’ve had to go back down many times to pick up people’s masks. In most cases, we don’t find it back. Secondly, a mask on the forehead is one of the tell tale signs of a diver in distress. You don’t want the boat crew to think you’re having a panic attack, do you? And the third (and maybe most important) reason: it looks really stupid.

9. Bring single-use plastic on the boat

We all know we shouldn’t use single-use to begin with. But unfortunately manufacturers are still using it for packaging, so we can’t always get around it. Especially when on holiday, we don’t always have our usual plastic-free alternatives with us. But maybe it’s time to change that? Why don’t we make a reusable bottle, food container and cutlery just as standard on our packing list as sunblock and a bikini?

Avoiding single-use plastic should be done on a day-to-day basis, but it’s especially important on a boat. Being on a boat usually means there will be wind, and empty plastic packages are very easily blown away. I don’t need to tell you where they end up. Most dive operators nowadays are not bringing single use plastic on their boats anymore (if they do, talk to them about it!). But often they don’t ask their guests to do the same, even though it’s completely unnecessary! If you like your dive sites to be plastic-free (don’t we all?), intentionally bringing plastic to the very place we want to keep clean, doesn’t really make sense.

Things You Should Never Do In Scuba Diving: Single-Use Plastic
I found this plastic bag floating around on the dive site. It was probably brought onto the dive boat by someone, then blown away by the wind.

10. Dive without dive insurance

Diving without dive insurance is like traveling without travel insurance: not very smart. But what if you already have travel insurance? Make sure you double check the terms and conditions! Scuba diving is often classified as a ‘high risk activity’ and those are usually not covered. That also applies to any scuba gear you bring on your trip.

When practiced responsibly, diving is a relatively safe sport, but when a problem arises it can be an expensive one. That’s partly because dive destinations are often far from medical help, so you’ll need to be transported by air. But it’s also because dive accidents require specialized treatment. Even when diving conservatively and within limits, decompression illness is always a risk. The cost of hyperbaric treatment depends on the severity of a particular situation, but can easily cost a few thousand dollars.

I have my dive insurance with Divers Alert Network (DAN). It’s an international organization that specializes in scuba diving and offers global insurance. They give excellent advice and assistance to all sorts of dive-related problems. They also have a list of every hyperbaric chamber around the world, and assist in getting you there as soon as possible if needed.

Never have I ever …?

Writing all of this does not mean I’m some kind of scuba saint. I’ve also been guilty of breaking some of these ‘rules’ every now and then, but I try to avoid it as much as possible. So I’m just curious: how many of these points are you guilty of? And will reading this change anything in your current dive behavior?


    • Iris Reply

      thanks so much! And now I know the name of your dive shop yayyyyy 🙂

  1. I love it, especially as it is not just about breaking official rules but it also takes good judgement and community practices into consideration. Well done!

    • Iris Reply

      Hi Charlie, thank you for the compliment. You may repost it in Korean if you credit me as the author and link to my website to the original article. And if you could also share the link with me when you publish it that would be great 🙂

  2. Richard Dennis Reply

    Great article! I will read it over a few times. I know when I was diving in the Bahamas none of this was in my training. Would love to come dive again in the Philippines. I definitely need more training.

    • Iris Reply

      Thank you Richard! You’re always welcome to come and dive in the Philippines 🙂 And if you have any questions please feel free to reach out!

    • Thabks so much
      You hit the almost important things
      They all really relevant
      I like (5&8)
      Thanks it was great notes.

  3. Really enjoyed this post Iris! Particular thanks for the recommendation on dive insurance, much appreciated!

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