The Port of Belfast is Northern Ireland's principal maritime gateway, serving the Northern Ireland economy and increasingly that of the Republic of Ireland. It is a major centre of industry and commerce and has become established as the focus of logistics activity for Northern Ireland. Around two thirds of Northern Ireland's seaborne trade, and a quarter of that for Ireland as a whole, is handled at the port which receives over 9000 vessels each year.

With almost two million passengers and half a million freight units annually Belfast is Ireland's busiest ferry port. It is also Ireland's leading dry bulk port, dominating the market with regard to imports of grain and animal feeds, coal, fertilisers and cement, and exports of scrap and aggregates. Over 95% of Northern Ireland's petroleum and oil products are also handled at the Port.