Anchoring in the Caribbean: The Season, the Trade Wind and the Rules Island by Island

The Season: December to May, and the Box

The Caribbean sailing year has two halves and a hard line between them. The cruising season opens as the charter fleets come back to life in November and December and runs to April or May, when the wind softens, the crowds go home and the first tropical waves start rolling off Africa. The Atlantic hurricane season, as defined by the US National Hurricane Center, runs from 1 June to 30 November, with the statistical peak from mid-August to mid-October.

Those dates matter to a boat for a reason that has nothing to do with weather forecasts: insurance. Most yacht policies written for the region carry a named-storm or seasonal clause, the “hurricane box”, that restricts where the boat may be, or how it must be stored, between roughly June and November. The box is drawn differently by every underwriter, but the common shape puts its southern edge near 12°N, which is why Grenada, Carriacou and Trinidad fill with boats each summer while Antigua and the Virgins empty. Some policies accept a boat hauled and strapped down in the box; some want it afloat below the line. Read yours before you plan the summer, and treat the line as a guide, not a guarantee: Hurricane Beryl crossed the southern Grenadines at 12°N in July 2024, and the Grenadines itinerary covers what it changed ashore.

Inside the season, the months are not equal. Here is the year as an anchoring calendar rather than a sailing one, because the two disagree.

The Trade Wind and the Ground Swell

The engine of the whole region is the north-east trade wind, blowing from between east and north-east at 15–25 knots for most of the season and rarely dropping below 12. In late December and January the Christmas winds arrive: a stronger, more northerly run of 25–30 knots that can last a week. Every anchorage in the Eastern Caribbean is designed around this wind. The islands run north-south, so their west coasts are the leeward sides, and almost every bay you will sleep in faces west into flat water with the trades blowing over the hill behind it. The windward coasts are left alone.

That layout has one flaw, and it arrives in winter. Atlantic depressions passing far to the north send a long, low swell down the ocean, the north swell or ground swell, with periods of 12–16 seconds and heights that look harmless offshore. When it wraps around the northern tip of an island and runs down the west coast, every bay that is open to the north-west starts to roll. Boats lie to the wind, beam-on to the swell, and roll through 30 degrees all night. Anchorages that are perfect in April are untenable in January, and the bay with a headland or a reef to its north is suddenly the only one worth having. The surf forecast, not the wind forecast, tells you where to sleep from December to March.

Two remedies. A stern anchor, laid from the dinghy so the boat can be hauled round to face the swell, turns a roll into a gentle pitch. Simpler and nearly as good is a swell bridle: a line from the chain led aft to a stern cleat, the chain then eased so the boat lies at an angle to the wind, bow to the swell. Either way, set the alarm a little wider, because the boat is now held where the wind did not put it.

Why a Caribbean Anchor Fails on the Night the Wind Moves

Here is the region's signature problem. In a Mediterranean or northern European anchorage the wind shifts, the tide turns, and the boat wanders around its swing circle several times a night, and an anchor that survives a week of it has been tested from every direction. In the Caribbean the trade wind pins the boat at the far edge of the circle and holds it there, on the same bearing, for the whole stay. The rode is straight, the anchor is pulled from one side, and the boat never swings. It feels like the most secure anchoring you have ever done.

It is secure for exactly as long as the wind does not move. A night squall veering through 40 degrees, a north swell setting the boat sideways, a rare westerly ahead of a front: the anchor is now being loaded from a direction it has never been pulled from. That is when the fluke lying across a rubble patch rolls out, or the one set in a skin of sand over hardpan breaks free. The Caribbean drag rarely happens on the windy afternoon. It happens at two in the morning, in a squall, when the boat is suddenly somewhere it has not been all week. Our guide to why anchors drag has the mechanics; the fix here is to test what the wind will not.

Anchoring Technique: Sand Over Rubble, 4–6 m, Back Down Hard

The good news is that the seabed is generous. Most Caribbean anchorages are sand over coral rubble in 4–6 m (13–20 ft), with a strip of turtle grass or a scatter of coral heads to avoid. The holding ground is excellent where the sand is more than a hand deep and poor where it is a skin over rock. You cannot tell from the surface, but you can from a snorkel, which is why Caribbean regulars swim the anchor after it is set: shank buried, chain leading down into the sand, not across a rubble bank.

1. Pick a sand patch you can see. Pale turquoise is sand, dark patches are grass or coral, brown is reef. Anchoring on coral is illegal in every marine park in the region and destructive everywhere else; the French islands protect their seagrass beds as well.
2. Lay 5:1 chain and back down hard. In 6 m with a 1.5 m bow roller that is 35–40 m of chain. Then reverse at half throttle for 30 seconds and watch a transit ashore. The wind will hold the boat exactly where it ends up, so this is the only load test the anchor will get from this side.
3. Test the other side yourself. With the engine, motor slowly at 45 degrees to the wind on either bow and let the chain come tight from a new angle. Ten seconds each way. If the anchor is going to roll out of a rubble patch, you want it to do so now, in daylight, with you at the helm.
4. Rig a snubber. A trade-wind anchorage is a constant 20-knot load on the bow roller, all day and all night. A 5–8 m nylon snubber takes the snatch out of it and silences the chain.
5. Set the alarm on the anchor, not the boat. Detail below.

The full method, scope arithmetic and the setting sequence are in our guides to how to anchor a boat and anchor scope; this page is about what the Caribbean changes.

The alarm radius for a boat that does not swing

Because the boat sits at the rim of its circle, an alarm centred on the boat's current position is centred on the wrong thing: the boat is already at maximum distance from the anchor, and the first swing in a shift will trip it for no reason. Centre the alarm on the anchor (mark the position as the chain goes down, or walk the marker back along the chain bearing). Then set the radius to chain out + boat length + margin. In 6 m with 35 m of chain, a 12 m boat and a 15 m margin for GPS scatter and stretch, that is about 60 m. In 10 m with 50 m of chain on a bigger boat it is nearer 90 m. In the volcanic bays of Martinique and Guadeloupe, where the shelf drops from 6 m to 30 m in a boat length and you anchor on the edge with more chain than the depth suggests, go wider still. On a mooring ball, where there is no chain of your own, tighten to about 40 m so a parted pennant shows before the boat reaches the next ball. The GPS accuracy guide explains where the margin figure comes from.

Reef entrances

The Grenadines, the Bahamas and the outer BVI put a reef between you and the anchorage. The rule set is short and has no exceptions. Enter with the sun behind you, so the colours read true: mid-morning for a westward entrance, mid-afternoon for an eastward one. Eyeball navigation, one person on the bow, the chartplotter for orientation only, because surveys here can be decades old. Never at night, never with the sun ahead, never in rain. The Anegada approach in the BVI itinerary and the Tobago Cays entrance in the Grenadines week are the two worked examples on this site.

Island by Island: How the Rules Change

British Virgin Islands: the mooring economy

Sixty islands round the Sir Francis Drake Channel, 15–20 knot trades and sand bottoms make the BVI the gentlest place to learn. What makes it particular is the mooring ball. The popular bays are park or privately run mooring fields, first come first served or reservable through an app, and the day's decision is not where to anchor but when to arrive: by early afternoon in season, or you anchor outside the field. Anchoring is free on sand in most bays outside the park areas. The BVI anchoring guide covers the rules, the permits and the best anchorages; the itinerary covers the classic week.

US Virgin Islands: the federal park

Two hours west and a different country. Roughly two-thirds of St John's coast belongs to Virgin Islands National Park, and the Park Service names two areas in park waters where you may anchor at all. Everywhere else on the island you pick up a park mooring and pay the nightly fee before dark. St Thomas and St Croix, by contrast, are free anchoring with traffic and open water respectively as the hazards. US entry formalities apply. The USVI anchoring guide has the mooring fee, the two anchoring areas and the customs route from the BVI.

French islands: EU rules and buoy zones

Guadeloupe and Martinique are France, and so the EU. Clearance is done online at a chandlery or café terminal for a small fee, with no cruise tax and no per-head charge. In return the French state protects its seabed the way it does in the Mediterranean: seagrass beds and coral are off limits to anchors, and since 2013 Martinique in particular has been converting its best bays into organised mooring zones, one after another, with anchoring banned inside and a paid buoy in its place. The Cousteau Reserve off Guadeloupe's Malendure is buoys only. The list grows every season, so what was free anchoring on the last cruise may not be on the next. Both the Martinique and Guadeloupe weeks map which bays are which for 2026–27, and both cover the second French peculiarity: volcanic shelves that fall into deep water within a boat length of the anchor.

The Windwards: boat boys, marine parks and the Pitons

From Martinique south through St Lucia, St Vincent and the Grenadines to Grenada the islands are further apart, the passages between them are open Atlantic in 20–25 knots, and the anchorages are reefs and headlands rather than enclosed bays. Each island is an independent state with its own clearance and its own per-person entry tax. In many bays boat boys meet you on the way in, offering a mooring, ice, bread and a stern line ashore; agree the price first and pay the person who did the work. Two places have their own rules. The Tobago Cays in the Grenadines are a marine park with a per-boat and per-person fee whether you take a park buoy or anchor on the sand behind Horseshoe Reef. St Lucia's Pitons are a UNESCO World Heritage marine management area and are buoys only: no anchoring under the peaks. The Grenadines itinerary has the park fees, the post-Beryl state of each island and the alarm radius for a reef anchorage with nothing but the Atlantic behind it.

Bahamas: the permit, the banks and the Bahamian moor

The Bahamas sit outside the Caribbean proper, 700 islands on banks so shallow that depth is read by colour, and they run on a different physics. Here the current rather than the wind decides how the boat lies: a metre of tide moving across the banks pours through every cut between the cays and reverses every six hours. Anchored near a cut, the boat sails over its own anchor twice a night, which is what the Bahamian moor is for: two anchors laid up and down the current so the boat pivots in place. A cruising permit is issued on arrival and, since 1 April 2026, carries an anchorage fee scaled to boat length; once you hold it, anchoring is free everywhere the Exuma Cays Land & Sea Park does not say otherwise. The Bahamas anchoring guide has the fee schedule, the colour chart and the moor step by step.

Clearing In: Every Island Is a Country

A passage from Antigua to Grenada can mean six sets of customs officers. The procedure is the same everywhere in outline. Hoist the yellow Q flag as you enter territorial waters and go directly to a port of entry. Nobody but the skipper goes ashore until the boat is cleared. Present the ship's papers, passports, crew list and the outward clearance from the last country, which you will need every time. Many Eastern Caribbean states now take an online pre-arrival declaration through systems such as SailClear or eSeaClear, which shortens the queue but does not replace the visit; the French islands do the whole thing at a terminal; the USVI and the Bahamas have their own systems. Fees, taxes, weekend overtime and the length of stay granted vary by island and change with each budget, so we keep them in the island guides.

The Night Watch in a Wind That Never Stops

The Caribbean is where a GPS anchor alarm earns its place more than anywhere else we write about. The steady trade wind makes the anchorage feel safe and leaves the anchor untested in the same stroke. You will not be awake for the squall that swings the boat at two in the morning, and the boat gives no warning before it goes: no change in the wind noise, no new motion, because both were already there. The alarm is the only thing aboard that notices the boat has moved to a place it has not been all week. Centre it on the anchor, set the radius to chain plus boat plus margin, and let it run every night of the season, including the ones on a mooring ball, where the pennant you did not inspect is the ground tackle you are trusting. Our overnight anchoring guide is the general version; every island guide on this site gives the radius bay by bay.

The Bottom Line

Sail December to May, be south of the box or out of it by June, and choose your winter bays by the swell forecast rather than the wind. Anchor on sand in 4–6 m, lay 5:1, back down hard and then, because the trade wind will only ever load the anchor from one side, load it from the other side yourself before you trust it. Learn the rules of each island as you cross into it: balls in the BVI, the park in the USVI, buoy zones on the French islands, boat boys and marine parks in the Windwards, the permit and the tide in the Bahamas. And set the alarm on the anchor every night, because in the Caribbean the wind never changes, so the boat never swings, and that is exactly why the anchor that has not been tested from the other side drags the first time it does.