Belfast Harbour handled a record 23m tonnes of cargo in 2014, up 1.6% on 2013.
The performance is 46% above the low point of the recession in 2009.
Trade sectors which grew well in 2014 included stone exports which were up 18% and steel which was up 38%.
The level of new car imports also rose by 10% to 48,000, its highest level since 2007.
Roy Adair, Belfast Harbour's chief executive, said that surpassing 23m tonnes was "a major achievement" driven by an ongoing investment programme.
He said the performance had also been supported by major investments from customers such as Stena Line which has introduced a third ship to its Belfast - Liverpool service.
Mr Adair said the increased activity reflected a pick-up in the economy across the island of Ireland.
"Increased steel imports, for example, reflects greater manufacturing activity, especially in the Republic of Ireland, while the improvement in freight, containers and new car imports suggests a modest pick-up in consumer confidence," he said.
The amount of cement moving through the port increased fivefold to 79,000 tonnes.
However, total cement tonnages remain less than one third of pre-recession levels, reflecting the continuing depression in the construction industry.
Ferry passenger numbers remained steady during 2014 at 1.4m while cruise passengers calling at Belfast increased by 23% to a record 112,000.