Ship routing is defined as a procedure to determine an optimal track for ocean voyages based on weather and sea conditions, and a ship’s individual response characteristics in waves. This paper describes an algorithm for finding the optimum path of a ship in a realistic irregular seaway, and its application for some typical coastal routes of India. The algorithm requires the irregular directional wave spectra as input. This oceanographic data set is generated using the satellite data provided by the meteorological department. There are a number of different approaches to calculate the shortest path/route between two nodes representing the start and destination ports. In this work, the Dijkstra’s algorithm which is based on the application of optimal control theory and dynamic programming techniques has been applied to obtain reliable optimum routing in random sea state. Loss of speed of a vessel in a seaway is not always due to the additional resistance in waves: the speed is often voluntarily reduced in order to decrease the violent heaving and pitching motions of the ship. In this ship routing algorithm, both speed loss due to wave resistance and voluntary speed reduction to control the motion, have been considered for the path finding algorithm.