Popular with tourists and anthropologists alike, the islands form India's most isolated state. They are best known for dense rainforests, coral reefs and hunter-gatherer tribes who have long resisted contact with outsiders.
The search for Flight MH370 turned west toward the islands after Malaysia's air force chief said military radar had detected an unidentified aircraft suspected to be the lost Boeing 777 to the west of Malaysia early on Saturday.
On Thursday, two sources told Reuters the unidentified aircraft appeared to be following a commonly used navigational route that would take it over the islands.
The Indian Navy has deployed two Dornier planes to fly across the island chain, a total area of 720 km (447 miles) by 52 km), Indian military spokesman Harmeet Singh said in Port Blair. So far the planes, and a helicopter searching the coast, had found nothing.
"This operation is like finding a needle in a haystack," said Singh, who is the spokesman for joint air force, navy and army command in the Andaman and Nicobar islands.
The Defence Ministry said the Eastern Naval Command would also search across a new area measuring 15 km by 600 km along the Chennai coast in the Bay of Bengal.
The shape of this area, located 900 km west of Port Blair, suggested the search was focusing on a narrow flight corridor.
Chinese Foreign Ministry spokesman Hong Lei said China appreciated India's search efforts. Most of the passengers on Flight MH370 are Chinese.
On standby is India's most advanced maritime air surveillance plane, the P-8I Poseidon, a long range anti-submarine variant of the US Navy's P-8A. India, the first overseas customer for the aircraft, has ordered eight P-8Is.
Indian ships are also helping the search by more than a dozen nations for the missing plane, one of the most baffling mysteries in the history of modern aviation. The ships are searching an area north of Sumatra, in the south Andaman Sea.
Andaman and Nicobar is of strategic importance for India, because of its location near the busy Malacca Straits shipping route. Over the past decade, India has built up its military presence on the islands with the joint command.