There are many words for ‘ocean’ in Sanskrit: besides sāgara and samudra, we come across terms like abdhi, ambu[ni]dhi, ambho[ni]dhi, arnava, udadhi, jala[ni]dhi, payodhi, vāridhi, vārirāśi, varunālaya, sindhu, and others. But the abundance of expressions to denote ‘the sea’ or a particular ocean should not make one expect a rich Indian literature on maritime themes. There is ample evidence for metaphorical references to the ocean. Ships travelling to foreign countries and coming from there to India, as well as seaports and harbours where they land, are frequently mentioned. But documents systematically dealing with several aspects of maritime life are lacking, not to speak of maps recording the spatial extension of the Indian Ocean or its segments and the location of its anchorages. Some of the texts may be lost, but indigenous historiographic or encyclopaedic works about maritime activities do not seem to have existed in premodern, or to be precise, in pre-Islamic, India. Therefore, foreign sources are of great importance. A few glimpses of maritime contacts can also be gained from Indian inscriptions. The results of maritime and coastal archaeology should, of course, be consulted as well.