The maritime boundary between India and Sri Lanka was established though a pair of bilateral Agreements that were reached in 1974 and 1976 and spans some 288 km from the tripoint with the Maldives in the west to the 200 nautical mile limit of India and Sri Lanka in the east.

The portion of the boundary that passes through the Palk Strait, which is defined as historic waters, was established based on the principle of modified equidistance in a 1974 Agreement. The boundary in the Indian Ocean/Gulf of Mannar and in the Bay of Bengal was established in 1976 and follows a simplified equidistance line.