Why Halong Bay Has Over 1,600 Islands: Nature, Legends & Secrets

When people first hear that Halong Bay in Vietnam has more than 1,600 islands and islets, it often sounds like an exaggeration. How can one bay host such an extraordinary seascape? The answer lies in a fascinating blend of natural history, cultural legends, and ecological richness that makes Halong Bay one of the world’s most breathtaking destinations.

In this guide, we’ll explore why Halong Bay has over 1,600 islands, uncover its geological origins, learn about the myths behind the rocks, and discover the most iconic spots you should visit on your trip.

An Introduction to Halong Bay’s Unique Landscape

Designated a UNESCO World Heritage Site, Halong Bay is one of Vietnam’s most famous natural wonders. Stretching across an area of around 1,500 square kilometers, the bay is home to a maze of limestone pillars, jungle-clad islands, hidden lagoons, and pristine beaches.

A few quick facts:

Halong Bay features 1,969 islands and islets (UNESCO), of which about 1,600 form the core heritage area.
Most of the islands are limestone karsts, rising dramatically from emerald-green waters.
Many islands are named after their shape — such as “Fighting Cocks,” “Elephant,” or “Human Head.”

This rare landscape is one of the main reasons travelers worldwide flock to Halong Bay. But how did such a spectacular setting come to be?

How to Get from Hanoi to Halong Bay: Transport Guide

Geological Formation – Millions of Years in the Making

How limestone karsts were formed

Halong Bay’s islands began forming over 500 million years ago. The region was once a shallow tropical sea where marine life thrived. Over time, the remains of coral reefs and shells accumulated, creating massive layers of limestone.

Erosion, weathering, and natural processes

Through millions of years, tectonic movements, rain, wind, and seawater eroded the limestone. This slow process sculpted the islands into sharp cliffs, arches, and towers. The dramatic karst formations seen today are the result of nature’s constant reshaping.

The bay’s age and scientific research findings

According to Vietnamese and international geologists, Halong Bay’s unique landscape evolved during the Quaternary period (2 million to 11,000 years ago). Unlike other karst formations worldwide, Halong Bay is one of the most extensive and well-preserved examples of a tropical marine karst system.

Myths and Legends Behind the Islands

While science explains the natural formation, Vietnamese culture adds another layer of magic to Halong Bay.

The dragon legend of Halong Bay

The word “Halong” translates to “descending dragon” in Vietnamese. According to legend, ancient dragons were sent by the Jade Emperor to protect Vietnam from invaders. The dragons spat out jewels and jade, which turned into islands and islets, forming a natural fortress against enemies.

Local folklore connected to island names

Many islands have names inspired by their shape or local myths:

Fighting Cocks Island (Trong Mai Islet): Resembling two roosters facing off in the water.
Human Head Island: Looking like a person’s face when viewed from certain angles.
Stone Dog Islet: Shaped like a loyal dog guarding the bay.

Stories passed through Vietnamese history

Local fishermen often share tales of spirits living on certain islands, blessing travelers with safety. These stories highlight the deep spiritual connection locals have with Halong Bay.

Vietnam Launches Remarkable Cave Dining Accompanied by Cultural Spectacle

Famous Islands and Caves Worth Exploring

With over 1,600 islands, it’s impossible to see them all — but a few stand out for their beauty and accessibility.

Titop Island – views from the top

Named after Soviet astronaut Gherman Titov, Titop Island is famous for its sandy beach and panoramic viewpoint. A short hike rewards you with breathtaking views of Halong Bay.

Sung Sot (Surprise) Cave – the largest cave

This massive cave, discovered by French explorers in 1901, is Halong Bay’s largest. Inside, visitors find two vast chambers filled with stalactites and stalagmites, resembling natural sculptures.

Dau Be Island – hidden lagoons and biodiversity

Dau Be Island hides three inland lakes, accessible by kayak or boat at low tide. It’s a paradise for nature lovers, home to coral reefs and rare birds.

Cat Ba Island – gateway to Lan Ha Bay

The largest island in the area, Cat Ba, blends rugged cliffs with lush jungles. It also connects to Lan Ha Bay, a less crowded but equally stunning extension of Halong Bay.

Ecology and Biodiversity of Halong Bay

Beyond its striking appearance, Halong Bay is a living ecosystem.

Unique flora and fauna on the islands

Many islands support pockets of tropical forest, with species such as orchids, cycads, and palm trees. Some caves host endemic animals like white-headed langurs and geckos.

Marine ecosystems around limestone pillars

Underwater, Halong Bay harbors 200 species of fish and 450 kinds of mollusks. Coral reefs and mangroves play a vital role in supporting marine biodiversity.

Conservation challenges and protection efforts

Unfortunately, tourism and overfishing threaten this fragile environment. UNESCO and local authorities are implementing conservation projects, including waste management, stricter cruise regulations, and education for sustainable travel.

Visiting Halong Bay – How to See the Islands

Day cruises vs. overnight cruises

Day cruises (4–6 hours): Ideal for travelers short on time, covering highlights like Fighting Cocks Islet and Sung Sot Cave.
Overnight cruises (1–2 nights): Offer deeper exploration, including kayaking, squid fishing, and visiting quieter lagoons.

Best time to visit Halong Bay

Spring (March–May) and Autumn (September–November) provide pleasant weather and clear skies.
Summer is beautiful but can bring tropical storms, while winter is cooler and misty.

Tips for sustainable travel

Choose eco-friendly cruises.
Avoid single-use plastics.
Respect local wildlife and cultural sites.

More Than Just Islands

So, why does Halong Bay have over 1,600 islands? The answer lies in millions of years of geological evolution, enriched by Vietnamese legends that bring the rocks to life. Today, Halong Bay stands as both a natural wonder and a cultural symbol, inviting travelers to explore its mystery and beauty.

With its towering limestone cliffs, secret caves, and enchanting stories, Halong Bay is more than just a destination — it’s an experience of a lifetime.