The world famous Trincomalee natural deep water harbor is ranked as the second best natural harbor in the world. It is renowned for its large size (7.5 km2) and security and is the only harbor in the Indian Ocean that can be accessible to all types of craft in all weathers. It is about 10 times larger than the Port of Colombo. Admiral Lord Nelson had described this harbor as “the finest harbor in the world” when he visited aboard HMS Seashore in 1770 and the British described it as "the most valuable colonial possession on the globe providing the Indian Empire a security which it had not enjoyed from elsewhere". The habour is overlooked by terraced highlands and its entrance is guarded by two headlands, therefore, well protected from the monsoon winds. The three major bays namely, Back Bay, Dutch Bay and Inner Harbor that lie between the two headlands would be wonderful to explore during sunset when the fishermen return with their daily catches.
Trincomalee harbor has 2 segments, Inner Harbour and Outer Harbour. The outer harbour is composed of the Trincomalee Bay, which has the approaches to the Harbour and Koddiyar Bay into which the Mahaweli drains. At the place where the Mahaweli flows in to the bay there is a deep submarine canyon which runs to a depth of 400m about 4000 ft. from the shore.
Port Dimensions: Water- 1630 hectares, Entrance channel- 500 meters and Land Area- 5261 hec.
Trincomalee Harbour served as the main channel for sea borne trade during the Anuradhapura and Polonnaruwan periods. During the Kandyan Period (17th to 19th centuries AD), Trincomalee was the main port for the country. The seafarers Ptolemy (in the 2nd century BC) and Marco Polo (in the 12th century AD) and sea traders from China and East Asia had mentioned the port in their journals. There had been many sea battles during the colonial era nearby the Trinco Harbour as the Portuguese, the Dutch, the French, and the British tried to capture it in turn. The Trinco Harbour is also the home to major naval base in Sri Lanka which played a significant role during the 3 decade old civil war in Sri Lanka.
The Naval Dockyard (Naval Base) was built by the side of the Harbour by the British because of its sea route importance. Within the harbor is the Prima Flour Mills and the Tokyo Cement Company which works round the clock and gives employment to over 3500 people, mostly from Trincomalee. The Ashroff Jetty is popular for Commercial and Cruise ships.