A surge in visitors from over the border has helped grow the number of overnight trips in Northern Ireland by 11%, with the total spend heading towards £1bn in 12 months.
There were 4.98 million trips here between October 2016 and September 2017, with a total of 1.74 million overnight stays.
The figures from the Northern Ireland Statistics and Research Agency include those travelling from within Northern Ireland.
In the same 12-month period spending rose 18% to £950m compared to the same period a year earlier.
Breaking down the figures, trips from Britian and the Republic increased by 10%.
There was a surge of one-third in trips by visitors from over the border - rising to 524,000.
The figures contributed last year to the Giant's Causeway becoming the first Northern Ireland tourist spot to attract more than one million visitors in a 12-month period.
Tourism NI chief executive John McGrillen said: "Northern Ireland enjoyed overall growth from Great Britain, Europe and North America in the first nine months last year.
"Closer to home, Northern Ireland residents took more staycations and visitors from the Republic of Ireland continued to be motivated by value for money and spent £18m more than the same period last year, an increase of 45%.
"Our research shows that perceptions of Northern Ireland as a holiday destination have improved demonstrably in the Republic but, given that Northern Ireland still has a lower share of the overall holiday market, continued marketing investment will be vital if we are to maintain and build on recent performance.
"We are working very closely with the tourism industry to develop strategies that will contribute to long-term growth from all our key markets.
"This will mean capitalising on established experiences such as Titanic Belfast and the Causeway Coastal Route while developing a standout brand and investing in the right technology to give Northern Ireland a competitive edge in the international marketplace."
Colin Neill, chief executive of Hospitality Ulster, said while it was "great news" to see the growth in tourism, he added: "Imagine how much stronger the sector would be if the tourism programme budget hadn't already been cut.
"Clearly this is not a sustainable situation and if we want our tourism sector to continue to grow and to compete on the international stage it is clear that we cannot keep cutting the budget."
Meanwhile, Tourism Ireland has launched a new campaign to boost US visitors.
It has a target of growing American tourism numbers by 23% over the next three years.
Niall Gibbons, chief executive of Tourism Ireland, said: "The United States has performed exceptionally well in recent years.
"We are aware that continuing to deliver the level of growth seen in recent years will be challenging, as the competitive environment is becoming increasingly crowded."