Bonaire's geography: a coral island filed with two volcanoes

Where the three islands of the record lie

The country code BQ covers Bonaire, Sint Eustatius and Saba, the three islands that became public bodies of the Netherlands in 2010, and they sit in two separate parts of the Caribbean. Bonaire belongs to the Leeward Antilles, the chain off the Venezuelan coast that also holds Aruba and Curaçao. Britannica places it 80 kilometres north of Venezuela and 32 kilometres east of Curaçao. Saba and Sint Eustatius belong to the northern Leeward Islands, south of Sint Maarten and northwest of Saint Kitts and Nevis. Statistics Netherlands puts the two groups more than 800 kilometres apart.

Bonaire carries most of the land and nearly all of the people. The island is 38.6 kilometres from north to south and between 5 and 8 kilometres wide. About 800 metres off its west coast lies Klein Bonaire, uninhabited and almost flat, whose size the sources give differently: 6 square kilometres in one place in the Wikipedia article, 700 hectares in another and 8 square kilometres in Britannica. The southern tip of Bonaire is the southernmost point of the Netherlands, marked by a windsock in the national colours, with Venezuela about 90 kilometres beyond it.

The areas are those of the islands' Wikipedia articles and the populations those of Statistics Netherlands. The record's own total for the territory differs from the sum of these figures, and its height for Mount Scenery, 870 metres, is the one the Wikipedia articles give; the Dutch Caribbean Nature Alliance gives 887 metres.

How coral built Bonaire above the sea

Bonaire and the other ABC islands lie along the Leeward Antilles Ridge, pushed up where the Caribbean plate meets the South American plate. Geologists date the ridge to about 90 million years ago and disagree over whether Bonaire sits on the South American continental shelf or on the Caribbean plate. The Dutch Caribbean Nature Alliance describes the island as formed from ancient fossil reefs on the lip of a deep ocean trench that separates it from the mainland.

The visible island is coral that grew on a rising seabed and died when it reached the air. Britannica puts coral limestone at some 70% of the surface, and the name Kralendijk, coral dike, comes from it. Beneath it lie gently tilted carbonate rocks dated from the Cretaceous, roughly 90 to 100 million years ago, to the Miocene, about five million years ago, resting on an older igneous base. Where old sea levels cut into the rock, caves formed: the Wikipedia article estimates more than 200 on the island, some with Caquetío drawings, some sheltering bats and a blind shrimp.

The relief follows the rock. The north is hilly, and Brandaris rises to 240 metres inside Washington Slagbaai National Park. The south is almost flat and barely above sea level, which is what made it suitable for salt. Lagoons and inlets cut into the coast, Goto Lake in the north the biggest of them. The reef starts at the shoreline, because the tidal range is only 55 to 60 centimetres and is moved more by wind and air pressure than by the moon.

Why so little rain falls on Bonaire

The trade winds blow almost constantly from the east. The Wikipedia article on Kralendijk puts the dryness down to the divergence of the trade winds and a drying effect from winds running parallel to the South American coast. The Meteorological Department of Curaçao's climate normals for Flamingo Airport over 1971 to 2000 give an average air temperature of 28.0°C, a yearly rainfall of 463.3 millimetres and an average wind speed of 6.6 metres a second. The wettest month in those normals is November, at 95.9 millimetres; March and April averaged 13.2 millimetres each. The single wettest day on record in the series brought 175.8 millimetres, in July.

Averages hide how much a year can vary. The Wikipedia article on Kralendijk ties the short rainy season from October to January to the Southern Oscillation: it often fails in El Niño years, and in La Niña years rainfall has reached about 1,000 millimetres, as in 1970 to 1971, 1988 to 1989, 1999 to 2000, 2010 to 2011 and 2022 to 2023. The Wikipedia article on Bonaire gives a longer-term average of 520 millimetres, and Britannica says less than 500.

Bonaire lies outside the main development region for Atlantic hurricanes, though storms do reach it: Hurricane Lenny damaged its reefs badly in 1999. Saba and Sint Eustatius, further north, are in the hurricane belt. Drinking water on Bonaire comes from a government desalination plant, in Britannica's account, and twelve wind turbines on the northeast coast have supplied part of the island's electricity since 2010.

The District Court of The Hague found on 28 January 2026, in a case brought by eight residents with Greenpeace Netherlands, that the Dutch state had failed to protect the people of Bonaire against the effects of climate change, and ordered an adaptation plan for the island by 2030. Norton Rose Fulbright's summary of the ruling notes that the Intergovernmental Panel on Climate Change counts Bonaire among the small islands particularly vulnerable to those effects. Bonaire: politics covers the case.

What lives in the salt pans and lagoons

About 10% of Bonaire's land is salt pan, the Wikipedia article says: shallow lakes cut off from the sea by ridges of dead coral. They catch rainwater and filter it, which keeps soil and nutrients off the reef. In the south the ponds of the salt works and the Pekelmeer around them hold brine shrimp and brine flies, and those feed the flamingos. The Wikipedia article counts between 2,000 and 7,000 Caribbean flamingos in the Pekelmeer area depending on the season, and the sanctuary there, closed to people, is one of four nesting grounds of the species.

BirdsCaribbean's survey for the Western Hemisphere Shorebird Reserve Network, which designated the salt ponds a site of regional importance in 2018, counted more than 20,000 shorebirds of 17 species using them in a year, among them at least 1% of the threatened rufa subspecies of the red knot. The salt works covered 3,700 hectares at that date, 2,700 of them artificial wetland.

Lac Bay on the southeast coast is a shallow lagoon behind a barrier reef across its mouth, ringed by red, black and white mangroves, with seagrass beds that serve as a nursery for reef fish and a feeding ground for green turtles and queen conch. Lac Bay, Klein Bonaire, the Pekelmeer, Slagbaai and Gotomeer are listed under the Ramsar Convention as wetlands of international importance. On land the dry scrub holds columnar cacti, the divi-divi tree and the yellow-shouldered amazon parrot, and the donkeys, goats and pigs brought by the Spanish in the 16th century still roam it. BirdLife International lists two Important Bird Areas outside the parks: Dos Pos, a former plantation of small hills and sheltered valleys with old mango trees beside Washington Slagbaai, and the Washikemba, Fontein and Onima strip of 5,959 hectares along the northeast coast, with three freshwater reservoirs.

Trees are scarce across all three islands. The Wikipedia article on the Caribbean Netherlands puts forest at about 6% of the land, 1,910 hectares in 2020, all of it naturally regenerating and unchanged from 1990, with about 17% of it inside protected areas. Most of that forest is on the two volcanic islands.

How the reef and the parks are protected

STINAPA was founded in 1962 to protect nature in the Netherlands Antilles and began on Bonaire, with a flamingo sanctuary and Washington park in 1969. The Slagbaai plantation was added in 1979 to make Washington Slagbaai National Park, which covers the island's northwest; the Dutch Caribbean Nature Alliance gives its area as 4,286 hectares, the Wikipedia article as 6,000.

The Bonaire National Marine Park was created the same year. It covers the sea around Bonaire and Klein Bonaire from the high-water line to a depth of 60 metres, about 2,700 hectares of reef, seagrass and mangrove, and it received national park status from the Netherlands Antilles in 1999. Klein Bonaire was bought by the island government in 1999 with help from the Netherlands and the World Wide Fund for Nature after developers proposed hotels on it, and it became part of the marine park in 2001.

The fringing reef holds about 60 species of coral and more than 350 recorded species of fish. Stony coral tissue loss disease has reached it. Diving is suspended at the sites off Washington Slagbaai, Klein Bonaire is closed to visitors in the afternoons and divers are asked to disinfect their gear between sites.

How Saba and Sint Eustatius differ from Bonaire

Saba is a single volcanic cone, roughly circular, whose last eruption was about 5,000 years ago according to both the island's tourism office and the Dutch Caribbean Nature Alliance. Cliffs of 100 metres or more drop to the sea on most sides, so it has no permanent beach and one landing point. Rainforest and, near the summit, cloud forest cover much of it. About 4.3 kilometres to the southwest begins the Saba Bank, a submarine atoll and fishing ground now a national park.

Sint Eustatius is ten kilometres long and saddle-shaped. The Quill, a dormant volcano of 602 metres, fills the southeast, its crater wooded with rainforest, and lower hills with drier savannah-like scrub hold the northwest. All its beaches are black volcanic sand, and Zeelandia is a nesting beach for endangered sea turtles. Its reefs, wrecks and lava flows lie in a marine park that encircles the island.

Both islands manage their nature through their own foundations, as Bonaire does through STINAPA. The Saba Conservation Foundation runs Mount Scenery National Park, which spans every vegetation zone from cloud forest to dry coastal scrub, and the Saba National Marine Park, set up in 1987 around the whole island; a separate unit patrols and surveys the Saba Bank. On Sint Eustatius the St Eustatius National Parks Foundation manages the Quill and Boven National Park, the marine park and the Miriam C. Schmidt Botanical Garden.

Where the people of Bonaire live

Kralendijk grew from the merger of the old settlements of Antriol, Nikiboko, Noord Saliña, Playa and Tera Kora along the sheltered west coast; the six points of the star on Bonaire's flag stand for the original settlements. Rincon, settled under Spanish rule in a valley in the north, is the only other town and still stands apart. Newer districts have been added around Kralendijk: Republiek and Santa Barbara against the hill behind it, Sabadeco on the coast beyond, and Belnem past the airport towards the salt pans.

The population has grown quickly. Statistics Netherlands counted slightly more than 15,000 people on Bonaire in 2011 and 26,552 on 1 January 2025, nearly 70% more, mostly through migration. In 2024 alone the number of residents born outside the Caribbean Netherlands rose by more than 1,345, mainly people born in the European Netherlands, Colombia, Curaçao and the Dominican Republic. Several villages that once stood in what is now the national park, among them Labra, Kunchi and Porto Spano, were later abandoned.