Ryanair carried over 9 million passengers in August, a 1% increase on the figure for the same month last year.
Annual traffic to the end of August was up 2% to over 80 million passengers.
The airline's load factor increased by 1% to 89% in the month of August.
Its load factor for the year to the end of August was 82%.
Ryanair says it is the first airline in Europe to carry over 9 million passengers in a month.
The airline's share price rose by 0.8% this afternoon in Dublin after yesterday's steep fall after it warned on its full year profits.