Seychelles Deep Dive: Granite Islands of the Indian Ocean
The Seychelles is geologically unique. While most oceanic island groups are volcanic — thrust up by hotspots or subduction zone volcanism — the Seychelles' inner islands are ancient Precambrian granite, remnants of the supercontinent Gondwana, marooned in the middle of the Indian Ocean when the tectonic plates drifted apart some 65 million years ago. The result is a landscape that photographs cannot fully capture: great humped boulders of pale grey granite tumble into water so clear it reads as weightless, the boulders continuing down to 15 or 20 metres below the surface in absolute visual clarity. Sailing the inner islands is a combination of pure beauty, technical navigation through coral-studded channels, and the challenge of finding shelter in an archipelago that lacks a true protected harbour outside Mahé's Port Victoria.
Two Distinct Worlds
The Seychelles divides cleanly into two sailing environments. The inner granite islands — principally Mahé, Praslin, La Digue, Silhouette, North Island, and the smaller granitic satellites — lie clustered within a roughly 50-by-80 kilometre rectangle north of the equator at approximately 4°S. These are hilly, forested, and deeply indented with anchorages behind headlands and in sandy bays. The outer atolls and coral islands — Aldabra, Cosmoledo, Astove, Farquhar, and Desroches, scattered across a vast ocean area extending 1,000 kilometres to the southwest — are flat, low, and surrounded by extensive reef systems. Reaching the outer group from Mahé requires a passage of 700 to 1,200 kilometres each way, which places them firmly in expedition territory.
Navigating the Inner Islands
Port Victoria on Mahé serves as the principal port of entry, immigration and customs clearing. The capital's harbour is busy with inter-island ferries and commercial traffic, but the yacht anchorage at the inner harbour, behind the commercial port breakwater, provides reasonable holding. From Victoria, the standard inner islands sailing circuit moves northeast to Praslin — about 45 nautical miles — anchoring off Anse Lazio beach on Praslin's northwest tip, where the water clarity is extraordinary and the white beach is backed by Vallée de Mai, the UNESCO palm forest. From Praslin, the short hop to La Digue (5 nautical miles) brings you to Anse Source d'Argent, regularly voted among the world's most beautiful beaches.
Navigation between the inner islands requires attention to the reefs that fringe each island and extend from headlands. The charts are generally reliable but the sheer visual spectacle — the granite boulders, the clarity of the water — can be distracting. A reliable echo sounder and careful watch-keeping are essential. Between Praslin and La Digue lies St Anne Bank, a shallow plateau that can create confused seas in any swell from the southeast.
Anchorages and Shelter
The Seychelles does not have the benefit of true natural harbours in most anchorages. The bays and channels provide shelter that is directional — excellent in northeast monsoon conditions but exposed or rolly in the southeast monsoon. Grand Anse Praslin on Praslin's south coast offers good southeast shelter. North Island offers anchorage in its western bay during the northeast monsoon. Silhouette Island, the large granitic island 20 nautical miles northwest of Mahé, has a beautiful anchorage at Anse Mondon on its northwest coast, sheltered in settled conditions but open to the northwest.
The southeast monsoon — the dominant wind from May to October — kicks up swell from the direction of the Southern Ocean and creates uncomfortable conditions in many of the inner island anchorages. Most sailing charter operations in the Seychelles focus their season on the northeast monsoon months (November to April), which offer settled conditions and the most manageable anchorages.
The Charter Scene and Bareboat Options
The Seychelles is one of the Indian Ocean's premier bareboat charter destinations. Dream Yacht Charter, Moorings, and several local operators maintain fleets based in Mahé (Beau Vallon) and on Praslin. A standard inner islands circuit — Mahé to Praslin, La Digue, Félicité, and back — works well in seven to ten days for a crew comfortable with coral navigation. For those unfamiliar with the Seychelles, taking a licensed guide or hiring a local pilot for the first entry to unfamiliar anchorages is strongly recommended.
Regulations prohibit anchoring on live coral anywhere in the marine parks, which include the Sainte Anne Marine National Park just off Victoria. The moorings in these parks must be used where available. Anchoring in sand, confirmed visually or by echo sounder, is permitted in unprotected areas.
The Outer Islands Expedition
Aldabra Atoll, 1,100 kilometres southwest of Mahé, is a UNESCO World Heritage Site and one of the largest raised coral atolls in the world. It harbours over 100,000 giant Aldabra tortoises — the only surviving population of their kind — along with nesting frigatebirds, sacred ibis, and magnificent frigate birds. Entry to Aldabra is controlled by the Seychelles Islands Foundation, and a permit must be obtained well in advance. The anchorage in the main pass is exposed to swell and the current runs strongly; Aldabra is a destination for experienced offshore sailors only.
Cosmoledo and Astove atolls, 50 to 100 kilometres east of Aldabra, are considerably less visited and offer spectacular fishing and diving in nearly pristine condition.
Weather and Sailing Seasons
The Seychelles lies within the transition zone between the northeast and southwest monsoons. The northeast monsoon (November to March) brings winds of 10-20 knots from the north to northeast, settled weather, and the best cruising conditions. The southwest monsoon (May to September) brings stronger, more boisterous conditions with occasional squalls. April and October are transition months with variable winds and a higher chance of localised thunderstorms. Cyclones are rare but not unknown this far north of the Mascarene cyclone belt, though risks are very low.
Explore on the Map
The inner granite islands of the Seychelles can be explored in detail on the map, while the outer atoll group — Aldabra, Farquhar, and the others — appears far to the southwest, illustrating the vast ocean distances involved in an outer islands passage. The Seychelles on the map puts both sailing worlds in their true geographic context, showing the scale of the archipelago across the Indian Ocean.