India's coastal cities have been playing a pivotal role in international relations through culture, commerce, and connectivity since the hoary past. In modern times, coastal cities such as Mumbai (formerly Bombay) on the Arabian Coast and Kolkata (formerly Calcutta) on the Bay of Bengal have been active actors in international affairs. While Mumbai has been the hub of international trade and commerce, Kolkata has been the junction of cultural bonhomie with Bangladesh and Southeast Asian countries, which gained more traction due to cross-border movements of technology, information, education, trade and finance, and artistic tools bolstered by the New Economic Policy beginning in the early 1990s. Indian states and metropolitan cities are enhancing their positions in international affairs with tangible gains. Mumbai is referred to as India's financial capital and the home to the headquarters of great global business houses and financial organisations. Similarly, Kolkata is known as the cultural capital of India (Sri Aurobindo, Tagore, Shanti Niketan, Bengali folk art and culture etc.) and a destination for foreign tourists, artists and curious researchers. This paper examines the growth and impact of city diplomacy in India through the prism of federalism in advancing local interests in international politics. It attempts to assess the role of Indian cities from a comparative perspective in the conduct of city diplomacy from economic and cultural aspects. [ABSTRACT FROM AUTHOR]