A Guide to Scuba Diving in the Tropics

A pair of lemon butterfly fishes. Image: Jo Akant

Scuba diving is a pursuit that is beloved by millions around the world. After all, the oceans cover 70 percent of the earth’s surface, and they are home to over one million species of marine animals. While colder waters have their own share of majestic wonders like whales, sea lions, and numerous species of sharks, the tropics is where the action is at.

Unbelievably blue waters, pristine white beaches, and spectacular coral reefs teeming with marine life. That’s what scuba diving in the tropics is about!


Why are tropical oceans so diverse?

Divers and a sea turtle. Image: Jacqueline Macou

Water is a far greater heat conductor than air, moving heat away from warmth up to 25 times.

This means submerged animals lose their body heat quicker and might have to warm up by basking in the sun or on hot rocks like turtles. In addition, animals with gills constantly move water in and out of their gills, further losing warmth.

Tropical areas provide greater levels of biodiversity in warm waters, with plenty of food and a predictable, comfortable environment.

Most marine animals live in coastal areas, where photosynthesis is possible. The tropical areas of the Caribbean, Asia, and the Pacific are dotted with hundreds of thousands of kilometres of coastlines spread across islands too numerous to count.

The most prolific coastal marine life is recorded in the Western Pacific Ocean, while the most oceanic groups hang out at 30 or 60 degrees north or south of the equator.

Some cool tropical marine animals

While the array of tropical marine life is sure to dazzle, some will always send a jolt of excitement and adrenaline through you.

Green Sea Turtle or Chelonia Mydas

Image: B. Phelan

The Green Sea Turtle can live up to 80 years in the wild and migrates long distances to feeding grounds and hatching beaches. They are a protected species, making it illegal to hunt, kill or harm them.

They feed on primarily seagrass in coastal reefs and can grow up to 1.5 metres long.

Black Tip Reef Shark or Carcharhinus melanopterus

Image: David Clode

Fear not, although imposing looking, these gentle reef sharks with a trademark black tip on its dorsal fin are usually timid and skittish.

They eat smaller fish, crustaceans, and sea snakes and can grow up to 1.6 metres.

Getting close to one for a better look will prove challenging unless you are in a dive site where the sharks are frequently exposed to divers.

Catching a glimpse of this common reef shark is often one of the most exhilarating experiences for any new diver. They always say, you never forget your first shark!

Whale Shark or Rincodon Typus

Image: NOAA

These gentle giants, although technically sharks, only eat plankton by opening their cavernous mouths and filtering water out through their gills.

They can grow up to 12 metres in length, although the largest recorded specimen was 18 metres!

The whale shark is the largest non-cetacean animal in the world. Cetaceans are a group of marine animals that comprise dolphins, whales, and porpoises.

Manta Ray or Manta Birostris

Image: B. Phelan

With a wingspan that can reach 7 metres, these rays are pelagic animals that migrate long distances.

They move through the water with wing-like movements of their pectoral fins, slow and regal.

Often, they are nicknamed ‘UFOs’, after their smoothly gliding, hovering movements.

Staying warm

Unlike thick, bulky wetsuits of our northern or southern counterparts, scuba diving in the tropics often requires just a thin rash guard to protect from cuts and scrapes and a pair of board shorts.

Every diver has a different cold tolerance and will require wetsuits of varying thickness and lengths. Wetsuits are mostly made of neoprene, a spongy material that traps the warm water generated by your body.

For warm water of around 28°C, all you’ll need is a rash guard and a pair of boardies, or if you steadfastly dislike the cold (like me), you can wear a 3mm shortie.

Anything from 25°C downwards and you might be more comfortable in a 3mm long wetsuit.

While the water in the tropics seldom gets below 20°C, the maximum thickness you’ll need is probably a 5mm wetsuit.

Whilst you can hire wetsuits and fins from dive shops and resorts, you’ll want to bring your own mask for comfort and your scuba diving watch. If budget is not an issue, you might want to also consider investing a a dive computer.

A diver watching a family of clownfish in an anemone. Image: Sebastian Pena Lambarri

The viz

The what?

‘Viz’ is diver slang for visibility, and is a key component of every dive. The clarity of the water in the seas of the Central Pacific are unparalleled relative to the abundance of marine life around.

Plankton, coral excretions and other microorganisms can often muck up the ‘viz’ of the water, so visibility ranges from dive to dive, even on the same day.

The visibility at most dive sites around the tropics ranges from 10 metres to a whopping 40 metres, but tends to range somewhere in between.

It is not uncommon to be at 20 metres and still be able to see the surface!

This incredible clarity, combined with warm, cosy waters and one of the most diverse ecosystems in the world make tropical diving immensely popular in these parts of the world.

The seasons

Diving in the monsoon season isn’t recommended! Image: Michelle Raponi

While living in the tropics is pleasant year-round, the same cannot be said of diving. Seasonal changes bring changes in water temperatures, clarity, and most importantly, wind.

Life in the tropics is seasonal. It can range from windy, wet, and dry, but one thing’s for sure, it’s always hot.

Tropical islands undergo monsoon seasons. While diving in monsoon seasons is possible for hardcore underwater enthusiasts, it is not for the inexperienced or nervous diver.

Monsoons bring rain, high wind, and clouds. While it’s unpleasant to dive in rain, it doesn’t matter once you’re underwater. It is when getting out of the water that a torrential downpour suddenly doesn’t look too forgiving.

With high winds come big waves. Getting in and out of the water or floating at the surface with three metre swells can turn stressful real quick.

Lastly, clouds affect the visibility of the water. Sunlight penetrates up to 200 metres but you start to lose colours at about 30 metres.

Without sunlight, visibility is even more affected and you might end up having a pretty bad time trying to find your dive buddy in just two metres visibility.

Dive training – agencies

Image: David Mark

So, you think you want to take the plunge and give diving a try? Learning to dive doesn’t have to be intimidating or particularly difficult.

There are various dive training agencies available scattered throughout the world.

These dive agencies have a set syllabus and method of teaching, and the dive centres around the world typically teach one or more methods.

Your first foray into the underwater world can start from a Discover Scuba one day course to try it out with minimal commitment, or the full Open Water Course which will certify you as a qualified diver.

The main dive training agencies are:

PADI – The largest and most prominent agency, PADI was set up in 1966 and stands for the Professional Association of Diving Instructors.

SSI – Started in 1970, Scuba Schools International training is available in dive centres worldwide.

SDI – Scuba Diving International was the recreational diving division that split from the technical diving agency, Technical Divers International, in 1988.

NAUI – The National Association of Underwater Instructors, NAUI is the oldest non-profit scuba certification operating out of Florida since 1960.

Dive training – courses

A myriad of dive courses await. However, as a beginner, your first two options are:

1. Discover Scuba Diving (DSD)

Image: Tania Dimas

The only two prerequisites for this course are:

  • Minimum age of 10 years
  • Reasonably good health

Suitable for those that want to experience diving without committing the time, resources and effort to a full course, the DSD course is a quick, easy introduction to the underwater world.

While not a certification course, the DSD teaches you some basics about the equipment, lets you experience how to breathe underwater and learn a few critical skills that you’ll need to dive.

It sets you on the right path to becoming a certified diver, and if you complete the DSD course, the credits can count towards the Open Water Course should you fall in love with the ocean and decide to become a certified diver.

2. Open Water Course (OWC)

Folks that experiment with the DSD course often decide to further their education with the Open Water Course.

Successful completion of the OWC will mean that you are a certified diver and can dive unsupervised with a buddy to a depth of 18 metres.

The OWC is a 3-5 day course that comprises three modules:

  • theory with an examination at the end of the course
  • pool sessions
  • 4 open water dives

Classes are typically held in groups of a maximum of four people. However, some groups are allowed to be larger if assistant instructors or divemasters are used.

The prerequisites for the Open Water Course are:

  • Minimum 10 years old. Divers from 10 to 14 years are awarded the Junior Open certification and automatically become Open Water Divers at 15.
  • Medically fit with no pre-existing health conditions or certain medications. The Diver Medical Form should be downloaded and checked whether a medical professional’s clearance is needed.
  • In addition, during the course, you’ll have to show the ability to:
    • Able to float or tread water without flotation aids for 10 minutes
    • Able to swim 200 metres unaided or 300 metres with mask, fins, and snorkel
Image: Deborah Bee

Continuing education

As the Open Water Course allows you to dive only up to 18 metres, many take a back-to-back course with the Advanced Course which allows for up to 30 metres.

The Advanced Course is a 3-5 day course that refines the skills learned in the Open Water Course.

After which, the sky’s the limit and who knows, you might be our next dive leader!

The underwater world in the tropics is an amazing, magical place that everyone should get to experience, whether snorkeling at the surface, or deep under it.

We hope to see you underwater soon. Happy blowing bubbles!




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