Which meridian forms the boundary line between the Indian Ocean and the Pacific Ocean ?

The boundary between the Indian Ocean and the Pacific Ocean is defined by the International Hydrographic Organization (IHO) as the meridian of South East Cape in Tasmania. This meridian is located at 146° 55' E (often rounded to 147° E in general texts). According to geographical standards, the Indian Ocean is delineated from the Pacific Ocean by the 147° east longitude . This line runs south from the southernmost point of Tasmania (South East Cape) to the Antarctic continent. While other meridians define different boundaries—such as the 20° E meridian at Cape Agulhas separating the Indian and Atlantic Oceans—the Tasmanian meridian serves as the official divide for the Indo-Pacific transition . Consequently, the meridian of Cape of Tasmania (South East Cape) is the correct geographical boundary line.

Sources

1. [1] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 16: India–Political Aspects > INDIA AND THE GEO-POLITICS OF THE INDIAN OCEAN > p. 63