Most scuba divers have been there – you’re heading out on the boat dive you’ve been dreaming of for months, but rough seas catch you off guard and you suddenly fear you might be about to see your breakfast again. Seasickness is more common than you’d think, even for the most seasoned scuba divers.

 Whilst it can feel quite debilitating in the moment, seasickness is relatively easy to overcome with over the counter medication, hydration, and patience, read on to learn what you can do to prevent seasickness, how you can ease seasickness in the moment, and what to do if you experience motion sickness underwater on a dive. 

What causes seasickness?

Put simply, seasickness is a form of motion sickness which is specifically experienced at sea. This motion sickness is caused by a conflict between your brain and your senses. Your inner ear is responsible for your balance, and along with your muscles it can sense that your body is moving around. If your eyes aren’t perceiving the same movement, your body sets off a stress response which can cause nausea, vomiting, and dizziness. 

How can I prevent seasickness?

If you’re predisposed to motion sickness, the simplest way to avoid it when scuba diving is by taking medication beforehand. There are lots of over-the-counter pills available from pharmacies which can be a huge help in avoiding seasickness. Make sure they are non-drowsy and check with your doctor or dive doctor before taking any medication and diving. Follow the medical guidelines in the package and your doctor’s advice.

For those who prefer to avoid taking pills, there are a few steps you can take to minimise the risk of feeling unwell. Avoiding large, heavy meals ahead of boat trips can help – opt for fresh vegetables and starchy foods over greasy, spicy, or acidic options. Stay well hydrated but ensure that there’s also some food in your stomach – the feeling of just liquid moving around in the stomach can increase feelings of nausea. Some divers also swear by seasickness wrist bands which work on the theory of pressure points.

How can I ease seasickness in the moment?

If you skipped the seasickness pills but find yourself feeling unexpectedly nauseous, there are a few tried and tested tactics to getting your sea legs back. Firstly, watch the horizon. Fresh air helps, and seeing the motion of the water helps your brain to realign with what your body and inner ear are experiencing which should ease the nausea.

 You can also look to natural methods of easing sickness. Ginger in any form is a classic seasickness cure. Some people swear by mint for the same stomach-settling properties. Green apples are also rumoured to be great for nausea; their high pectin content supposedly slows down digestion which in turn settles the stomach.

Will seasickness prevent me from scuba diving?

Seasickness in itself isn’t inherently dangerous, and it’s a lot more common than you’d think. If you’re feeling unwell on the boat, it’s likely you’ll feel better just by getting in the water as it’s often calmer under the waves than at the surface. However, although feeling sick and being sick isn’t necessarily harmful, the effects of it can cause some risks when you’re diving. 

 If you’ve been vomiting you’re likely to become dehydrated, and dehydration increases the risk of decompression sickness. If you’ve been sick prior to a dive, ensure that you drink plenty of fluids to rehydrate yourself. Sports drinks with electrolytes can be particularly helpful for rehydration. You should also consider taking on an easier dive with more conservative depth and time limits.  

What should I do if I feel sick underwater?

Whilst most seasickness subsides once you start your descent, if you’re particularly sensitive to motion sickness it’s possible to feel nauseous underwater too. This may be as a result of seasickness on the boat not easing, or could be caused by conditions under the water such as surge.

If you do find yourself feeling sick underwater on a dive, the most important thing to remember is to keep your regulator in. The human body’s first reaction after vomiting is usually a sharp intake of breath, so it’s extremely important that you keep your regulator in place if you throw up whilst scuba diving. This is a safety precaution to ensure you don’t try to take a breath and inhale a mouthful of water instead. 

You should physically hold your regulator in your mouth. The vomit will simply come out of the exhaust valves of your second stage, and as they work on a one-way demand valve you will still get a breath of (slightly vomit tainted) air when you next breathe in. You can also press the purge button whilst you’re throwing up to try to flush the reg out a little better. The one upside to all of this? Underwater residents love the free food, so you’ll get up close and personal with some fishy pals feeding on your leftovers.  

Whilst vomiting isn’t necessarily a dive-ending scenario, keep an eye on how you feel. If you continue to feel unwell or you’re fatigued after throwing up, remember it’s perfectly acceptable to cancel a dive at any time, for any reason. 

 Once you’re back topside you’ll need to dedicate a little more time than usual to cleaning your regulators, and if you’re concerned that anything is remaining in the internal parts then you should have them serviced by a professional. Do your best to clean them first and give them a heads up on why you’re sending them in, though! You should also apply the same courtesy if you’re renting equipment – offer to clean the regs yourself, but make sure the dive operator knows that they might need a bit of extra attention.