Andaman Islands

The Andaman Islands form an arc of 300-plus islands stretching 350 kilometres through the Bay of Bengal, roughly equidistant between India's eastern coast and Myanmar's Mergui Archipelago. The group sits at the convergence of two distinct water bodies: the Bay of Bengal to the west and north, the Andaman Sea to the east. This geometry, combined with the islands' location between 6°N and 14°N, produces one of India's largest tidal ranges. At Port Blair, spring range is 3.2–3.8 m, semidiurnal — the two daily tidal cycles track each other closely in height, unlike the pronounced diurnal inequality seen further north in the Indian Ocean. At Havelock and Neil Islands, the range decreases slightly to 2.5–3.2 m as the open sea geometry moderates the range away from the island-enclosed waters around South Andaman. The consequence of this range is strong inter-island tidal currents. The passages between South Andaman, Baratang, and Middle Andaman narrow to 2–4 km in places, and the tidal flow through these narrows runs at 2–4 knots at peak spring ebb. Boat operators running the Havelock and Neil Island ferry routes, and the smaller launches serving the Rutland Island and Little Andaman approaches, plan departures around the tidal flow through the passages. Crossing against a spring ebb in a 2-metre swell in the North Andaman Channel can double journey time and fuel consumption. Radhanagar Beach on Havelock Island's west coast — designated Beach 7 under the original survey numbering — has a consistent reputation as one of Asia's finest beaches. The beach faces west across the Andaman Sea and catches the full gradient sunset over open water. The intertidal zone here is active: the 2.8–3.2 m spring range exposes 60–100 m of clean sand at low water that is submerged at high tide. The Andamans' colonial history is as prominent as its marine ecology. The Cellular Jail at Port Blair, completed in 1906, was the British colonial government's most feared punishment posting — a solitary-confinement penal colony for Indian independence activists. The seven-wing radial structure, built directly on the Port Blair waterfront, is now a national memorial and the most visited historical site in the union territory. The coral reefs surrounding the islands were largely undisturbed until the 1990s and retain high coral coverage; the 2004 Indian Ocean tsunami caused localised reef damage but the ecosystem has largely recovered.