The Central Statistics Office said this was the first annual fall for the April-June period since 1991.
Read the full CSO report
Visits to Ireland in the quarter fell 12% from a year earlier to just over 1.9m.
Visitor numbers from the UK dropped by 16%, while the figure for the rest of Europe was down 10%. North American visits fell by 2%.
The CSO said annual comparisons should take account of the fact that Easter fell in the second quarter this year, but in the first quarter of 2008. As Easter usually boosts travel figures, this implies that the underlying falls in the second quarter this year may have been even bigger.
Spending figures for the quarter show that the amount spent by Irish people abroad exceeded the amount spent by visitors in Ireland by €468m.
The number of nights spent in Irish hotels dropped by 25% from a year earlier, while nights in guesthouses were down 8%.
