6 Forbidden Islands On Earth No One Is Allowed To Visit

In Hawaii, where approximately half a million tourists visit each month, there is an isolated island that even the people from the government are prohibited from entering. It’s been that way for the past 150 years, and nobody can really explain it.

There are a number of mysterious islands in the world, and access to them is limited for various reasons. So, what is really happening out there? Are these places hiding ancient secrets or just quietly recovering from human interference? Could they be untouched paradises, or are they more dangerous than they appear? Whatever the reason, these islands have a way of capturing the imagination and stirring up questions with no easy answers.

1. Niihau Island, Hawaii, USA

Niihau might look like just another quiet Hawaiian island, but it’s wrapped in secrecy. In 1864, King Kamehameha V sold it to Elizabeth Sinclair for $10,000. She moved her family there, brought crops – and immediately shut the island off to outsiders. To this day, even the governor of Hawaii requires permission to enter the island.

The roughly 70 native Hawaiians who live there speak a unique dialect and follow strict rules: no long hair, no earrings, and no breaking the silence. Visitors are forbidden from talking to locals, and even residents who leave are told not to speak about island life. There’s no phone service, no plumbing—just rainwater and a lot of questions.

The U.S. military uses locals for exercises, but are they just role-playing enemies, or is there something more sinister going on? Conspiracy theorists suggest experiments or even cover-ups involving ancient Hawaiian relics. Some believe the island hides sacred artifacts destroyed by missionaries in the 1800s—items that could be worth millions to the right collector.

Even President Franklin Roosevelt reportedly tried to buy the island in 1944, possibly to make it the UN’s home base. The family refused. The current owners, descendants of Sinclair, still won’t sell. This raises the question: What is truly hidden on Niihau that is valued at over a billion dollars?

2. Ilha de Queimada Grande, Brazil

Brazil says it closed Snake Island to protect the critically endangered golden lancehead viper, but let’s be real—no one’s buying that. Officially, the island swarms with venomous snakes, and these golden lanceheads are so deadly that even with an antidote, you might still bleed from your eyes, go into kidney failure, or die from brain hemorrhaging. This sounds like nature’s version of a bioweapon.

But here’s where it gets shady. Why are they only on this one tiny island? Why are they so numerous? Some speculate that the government may have been conducting experiments on bioweapons or snake venom pharmacology, and then sealed the island once things got out of hand. There are even tales of illegal research facilities deep in the jungle, now “abandoned” but still off-limits. And since no civilians are allowed, we’re stuck with secondhnd reports from researchers under tight restrictions.

Perhaps it’s an attempt to preserve the environment or a clever way to conceal a location that never existed. You’d think that with modern drone tech, someone would have leaked footage by now unless they have a counter for that, too.

3. North Sentinel Island, India

North Sentinel Island is off-limits for a reason, but is it truly about safeguarding the tribe? Officially, the Indian government says it’s shielding the uncontacted Sentinelese people from modern diseases. And yeah, they’ve been known to fire arrows at anyone who dares approach. But why has every attempt at peaceful contact failed so violently time after time?

North Sentinel has essentially acted as a real-life Area 51 since its discovery in 1771. In the 1800s, the tribe attacked a British crew. In 1974, the tribe shot arrows at a National Geographic team, causing them to bury all their “peace offerings” on the beach. American missionary John Allen Chau attempted to convert the tribe in 2018, but the tribe promptly killed him and left his body on the sand as a warning.

Some conspiracy theorists believe the island is a living human experiment: an isolated group either intentionally kept in the past or hiding something ancient and powerful. Others point to unexplained military flyovers and the eerie precision of the Sentinelese archers as proof they’re more advanced than they look. Whatever the case, no one’s getting within 9 kilometers of that piece of land. And that kind of security raises more questions than it answers.

4. Gruinard Island, Scotland, UK

For nearly 50 years, this small Scottish island was literally a biological weapon test site. The British government turned Gruinard into a toxic anthrax lab during WWII, allegedly to develop defenses. But who were they kidding? The experiment wasn’t about safety. This was a straight-up chemical arms trial.

They brought in sheep, blasted the island with anthrax bombs, and waited. Within days, animals were bleeding out and dying. But the spores didn’t just kill the cattle, and they permeated into the soil. It was so bad that the researchers had to douse the whole island in 280 tons of formaldehyde and even dig up parts of the land like it’s nuclear waste.

Here’s where it gets intriguing. The UK government only admitted this in the 1990s. Before that, the UK government simply labeled Gruinard as “off-limits” without providing any public explanation.  There were rumors of mutated animals, secret underground bunkers, and even whispers of contaminated people who’d been “taken away.”

Even after the “clean-up,” no one lives there. It’s supposedly safe now, but the UK government still owns it. So if it’s all fine, why hasn’t it become a tourist destination? Maybe it’s not about anthrax anymore, or maybe it never was. Some say it was a cover for darker Cold War experiments. Either way, you’re not likely to see vacation brochures for Gruinard anytime soon.

5. Heart Reef Island, Australia

Heart Reef is a little natural wonder nestled in the sparkling blue waters of the Coral Sea, close off Australia’s Whitsunday coast. It’s exactly what it sounds like: a coral formation that resembles a heart. Perfect, delicate, and almost unbelievably gorgeous. Discovered by a local pilot back in 1975, it quickly became a symbol of romance, wonder, and the incredible artistry of the natural world.

But here’s the thing: you can’t visit it!

You can’t swim there. You can’t snorkel or dive around it. And no, you can’t step foot on it either. And honestly? That’s a good thing.

Heart Reef is tiny—only about 17 meters across—and extremely fragile. Like, centuries-old coral-fragile. Even the smallest human disturbance could damage it beyond repair. That’s why the Great Barrier Reef Marine Park Authority has strict rules to protect it. No boats. No touching. No exceptions.

The only way to see Heart Reef is from the sky. Scenic helicopter or seaplane flights from Airlie Beach or Hamilton Island offer jaw-dropping aerial views—seriously, it’s like looking down at a secret love note written by the ocean. From there, you can enjoy a luxury experience that keeps a respectful distance—all without putting the reef at risk.

6. Maya bay, Ko Phi Phi Le island

There’s a reason Maya Bay feels like a dream the moment you see it. Tucked away on the uninhabited island of Ko Phi Phi Leh in Thailand, this little stretch of sand surrounded by towering limestone cliffs and impossibly blue water became iconic after Leonardo DiCaprio made it famous in The Beach. For years, it was the postcard image of Thai paradise—and people from around the world came chasing that postcard.

But paradise, it turns out, can be fragile.

After the movie’s release in 2000, Maya Bay exploded in popularity. And not just a little. At its peak, the bay saw around 5,000 visitors and up to 200 boats every single day. The crowds brought money and fame, yes—but they also brought anchors dropped directly on coral, sunscreen-polluted waters, and foot traffic that trampled fragile ecosystems. By 2018, over 80% of the coral reef was dead, and marine life had largely vanished.

That year, Thai authorities made a bold and heartbreaking decision: they closed Maya Bay to all tourism. What was meant to be a short break turned into years of healing. During that time, scientists and conservationists worked tirelessly to rehabilitate the reef and bring life back. Scientists replanted coral. Marine monitors watched for signs of life. And slowly, nature responded. The return of blacktip reef sharks—once chased away by the noise and chaos—became a symbol of cautious hope.

Maya Bay finally reopened in January 2022, but under strict new rules. The bay is now off-limits for swimming. No boats are allowed to dock on the beach. Visitor numbers are now capped, and access is carefully monitored. There’s even a scheduled annual closure during the rainy season (usually August through September) to give the ecosystem time to rest.

It’s not the free-for-all it used to be—and that’s a good thing.

Maya Bay still looks like magic. But it’s a different kind of magic now—one rooted in reverence, not rush. Tourists can still visit, but it’s no longer about getting the perfect Instagram shot. It’s about being part of a bigger story—a story about damage, responsibility, and the possibility of repair.