The short answer
The Andaman and Nicobar Islands, an Indian union territory in the Bay of Bengal, have no documented ancient Buddhist heritage. No excavated monasteries, stupas, inscriptions or pilgrim accounts are known to link the Andaman islands with the early Buddhist world. Writers sometimes suggest otherwise, usually because the islands lie between India and Southeast Asia and Buddhism travelled by sea, but that is an inference, not evidence. This article sets out what can responsibly be said.
Why the sea route does not prove a site
The spread of Buddhism across the Bay of Bengal is well documented in other places. Monks, merchants and texts moved between eastern India, Sri Lanka, Myanmar, Thailand and Indonesia over many centuries, a story told in the account of the spread of Buddhism and, for the regions touched by Theravada, the southern transmission.
Ships on these routes may have passed within reach of the islands. That does not mean temples or monasteries stood there. Without archaeological finds or reliable texts, there is nothing to name. If you find a website that presents a specific ancient Buddhist site in the Andamans, treat it with caution and look for an official or academic source.
What is actually known about the islands
The islands have been home for a very long time to Indigenous peoples, whose languages and ways of life are distinct from the mainland. These include the Great Andamanese, Jarawa, Onge and Sentinelese in the Andaman group, and the Nicobarese and Shompen in the Nicobar group. Their traditions are their own and should not be folded into a Buddhist narrative.
Much of the islands’ recorded modern history concerns colonial-era settlement and the penal colony at Port Blair, now remembered at the Cellular Jail memorial. In recent decades, settlers from mainland India and other regions have made the islands home to many communities. Some of those communities include Buddhists, and, as in other Indian cities, it is reasonable to expect small modern places of worship. Those are recent community institutions, not ancient pilgrimage sites, and a visitor should not expect an established pilgrimage circuit.
Restrictions every visitor should know
Many parts of the islands are protected, and access rules exist to safeguard Indigenous communities, some of whom have little contact with outsiders. Some areas are closed to visitors altogether, and approaching certain islands or tribal reserves is prohibited by law. Photographing or contacting Indigenous people may be illegal as well as harmful.
Entry permits, restricted-area rules and travel arrangements change, so check current official sources and government travel advice before planning anything. The monsoon season affects sea travel and weather, and cyclones occur in the region. This is general information, not travel advice.
Where to look instead
Readers who want to understand where Buddhism did take root in the region will find far better material in the places where the evidence is strong. In India, Buddhist sites by Indian state are concentrated in Bihar, Uttar Pradesh, Madhya Pradesh, Maharashtra and the Himalayan regions. Across the water, Myanmar, Sri Lanka and Thailand have long continuous traditions with many living temples.
Questions about Andaman sacred sites in general are a wider subject. Here the point is narrower: the Buddhist claim, as such, does not have a documented basis.
A note on careful sources
When you read about an unusual place and Buddhist history, a few questions help. Is there a named excavation? Is there a dated inscription or a specific text? Does an official heritage body list the site? If the answer to all of these is no, the claim is probably an assumption. A shorter, honest answer is more useful than a long speculative one, and the Andaman and Nicobar Islands are an example of a place where the honest answer is that nothing documented points to an ancient Buddhist presence.