Most travel lists tell you how to reach a place. This one tells you what happens when you ignore the sign. Some of these beaches are closed because the people who live there kill intruders. Some are closed because the sand is radioactive, the soil holds anthrax spores, or there is enough unexploded ordnance underfoot to end the trip permanently. The rest are held by navies, wildlife services, park rangers and private families who will happily have you charged with trespass. Every entry below answers the same three questions in the same order, why the place is off limits, who actually enforces it, and what happens to the people who try anyway. They are ordered by that last answer, deadliest first, so the list opens with islands that have killed visitors and closes with the ones that will simply turn you around at the dock. You can look at all of them. Landing is the problem.
North Sentinel Island, India, Where Trespassers Are Killed on the Beach
The Sentinelese have lived on this forested island in the Bay of Bengal for thousands of years and have refused contact for the whole of recorded history. They also have no immunity to ordinary illnesses like measles or influenza, so a single visitor could wipe out the population. India banned approach within five nautical miles under the Andaman and Nicobar Islands (Protection of Aboriginal Tribes) Regulation of 1956, and the coast guard patrols that buffer zone. The consequence is not theoretical. In November 2018 an American missionary, John Allen Chau, paid local fishermen to drop him near the reef. He was killed with arrows on the beach and his body was never recovered. Seven men who helped him reach the island were arrested as accomplices. Foreign nationals who try face prosecution, deportation and a ban on returning to India.