Diving at St. John’s Island, Singapore: A Hidden Marine Gem

Cuddlefish Divers
Sep 27
3 min read

When most divers think of Singapore, Pulau Hantu often takes center stage as the go-to training ground. But just a little further south, nestled in the Southern Islands cluster, lies a quieter treasure waiting to be explored — St. John’s Island.

As part of our continuing exploration of local dive spots at Cuddlefish Divers, this blog takes you beneath the waves of St. John’s to discover its history, unique dive environment, and the amazing marine life that thrives there.

A Brief History of St. John’s Island

St. John’s Island has a storied past — from its time as a quarantine station in the 19th century to today’s role as a leisure getaway and marine research hub. It’s also within the buffer of the Sisters’ Islands Marine Park, which means conservation plays a role in its management.

For divers, the real story begins once you slip below the surface, where Singapore’s corals, critters, and schools of fish remind us that marine life still flourishes despite urban development.

The Dive Environment

Depth: Shallow reef slopes, 5–15m. Perfect for both Open Water and Advanced divers.
Visibility: 2–6m is common, though it can surprise you with clearer conditions during calm tides.
Currents: Moderate but tide-dependent — planning around tidal charts is key.

St. John’s offers a step up from Pulau Hantu, giving divers the chance to hone skills in slightly more dynamic waters while enjoying a wider range of marine life.

Top 6 Marine Creatures to Spot at St. John’s Island

St. John’s is a living reef classroom, full of surprises big and small. Here are the creatures that divers love to encounter:

1. Nudibranchs (Sea Slugs)

Tiny but dazzling, nudibranchs are a macro photographer’s delight. Look out for the Pikachu nudibranch and colorful Chromodoris species hiding among corals.

2. Cuttlefish

These intelligent masters of disguise are often seen hovering over sandy patches, flashing hypnotic color waves as they communicate, hunt, or court.

3. Reef Fishes

Schools of snappers, rabbitfish, fusiliers, and damselfish bring bursts of silver and yellow to the reef. Damselfish in particular are fun to watch as they fiercely guard their algae “gardens.”

4. Crustaceans (Crabs & Shrimps)

From tiny sexy shrimps dancing on anemones to decorator crabs camouflaged with coral bits, St. John’s offers plenty of critters for the eagle-eyed diver.

5. Lobsters

Often hiding under ledges with only their long antennae visible, lobsters are elusive treasures in Singapore waters. Spotting one here is always a highlight!

6. Hawksbill Turtle (Occasional Guest)

Though rare, hawksbill turtles have been sighted gliding gracefully by St. John’s reefs. Their presence is always a reminder of why conservation matters.

Bonus finds: stingrays snoozing in the sand, flatworms drifting like silk, and the occasional grouper peeking out from rocky crevices.

Why Dive St. John’s?

Accessibility: Just 30 minutes by boat from Marina South Pier.
Biodiversity: Rich mix of macro and reef life — never the same dive twice.
Conservation Value: Diving here supports awareness of Singapore’s Southern Islands Marine Park and its ongoing protection.

At Cuddlefish Divers, we often say: “Protect what you love by experiencing it up close.” Diving at St. John’s Island is a way to rediscover Singapore through her resilient reefs and remind ourselves that you don’t need to fly across the world to find underwater magic.

Practical Tips for Diving St. John’s

Certified Guides: Dive with experienced local guides who understand the tides.
Safety First: Ensure your dive boat carries oxygen tanks and first aid kits.
Buoyancy Matters: Protect corals and critters with good control.
Plan Your Tide: Early morning dives often bring calmer conditions and better visibility.

Final Thoughts from Cuddlefish Divers

St. John’s Island may not yet be a household name among divers, but it deserves a place on your local dive log. From flamboyant nudibranchs to shy lobsters and the occasional turtle, every dive is a reminder that Singapore’s seas are very much alive.

As part of our ongoing blog series on Singapore’s Southern Islands, St. John’s proves that adventure, biodiversity, and conservation are only a short boat ride away.