Dublin to London is the second busiest international city route in the world.
The figures were released by IATA and say that 3.6 million people travelled across the Irish Sea in 2013.
That's up 6.9 percent on the same period in 2012.
Hong Kong to Chinese Taipei was the busiest air route last year.
The survey also showed that global air traffic grew by 5.1 percent in 2013 with airlines carrying over 3 billion passengers worldwide.
