Rising China and emerging India are becoming major maritime powers. Beijing and Delhi arebuilding powerful blue water navies to secure their vital interests far beyond their immediate shores. Beijing is looking beyond the Pacific to seek military access and special political relationships in the Indian Ocean. Delhi, in turn, is deepening its security partnerships with China’s neighbours in the Pacific. As the naval footprints of China and India overlap, their maritime competition has begun to roil the waters of the Indo-Pacific, the vast littoral stretching from Africa to Australasia. Invoking a tale from Hindu mythology—‘Samudra Manthan’—C. Raja Mohan tells the story of Sino Indian rivalry spilling over from the Great Himalayas into the Indian and Pacific Oceans. He examines the prospects for reducing Sino-Indian mistrust in Asia’s waters and expanding their maritime security cooperation. The unfolding of Sino-Indian rivalry inevitably draws in the United States, until now the dominant power in the Indian and Pacific Oceans. Despite the massive differences in the current naval capabilities of China, India, and the United States, the three countries are locked in a triangular dynamic that is shaping the strategic future of the Indo-Pacific.