Eamonn O'Reilly, the chief executive of Dublin Port, is to leave his post in August.
Mr O’Reilly has been the CEO at the port for 12 years.
"When I took the job in 2010, I did not envisage that I would still be here twelve years later," he said.
"I have relished every day of my time in Dublin Port and enjoyed the challenge of developing and implementing Masterplan 2040."
"Having gone through Brexit and with all three Masterplan projects up and running - two under construction - it’s the right time for me to move on."
During the period of Mr O’Reilly’s tenure, volumes through the port have risen by a quarter and profits have also increased by a third.
€500m has also been invested in the port’s infrastructure.
However, calls have also grown from some interest groups during that time for the port to be relocated to another area outside of Dublin city, in order to free up development land for housing and commercial property.
The board said it has begun the process of finding a replacement or Mr O’Reilly.
"The position of Chief Executive of Dublin Port is both challenging and exciting and our challenge now is to ensure that the recruitment process that has commenced will attract a strong field of candidates, leading to the appointment of a worthy successor to Eamonn," said Jerry Grant, chairman of Dublin Port.
