MP Martin Caton will be standing down at the next General Election, it has been confirmed.
The Welsh Labour Party said Mr Caton will not be contesting his Gower constituency seat at the next election.
A former Mumbles town and Swansea city councillor, Mr Caton was elected to Parliament at the 1997 General Election, following the retirement of Gareth Wardell, and retained his seat at the following three elections, in 2001, 2005 and 2010.
As Gower MP Mr Caton was at the forefront of last year's save Swansea coastguard station campaign and spoke about the potential dangers the closure would bring at the Commons.
"I shall be making the strongest possible case for the retention of the Swansea coastguard station, which is not only the busiest coastguard station in Wales, but one of the busiest in the country dealing with both sides of the Bristol Channel," he said before the debate.
Mr Caton added at the time: "Swansea coastguard station liaises with six different police forces and goodness knows how many ambulance services, and the local knowledge held by those who work at the station is second to none.
"The station is in a strategically excellent location, and is situated in a huge modern building that has excellent facilities that suit its purpose very well."
In the last election he retained his seat with a majority of 2,683 from Conservative candidate Byron Davies.
As well as his local duties, Mr Caton sat on the Welsh Affairs select committee between 1997 and 2005 and is currently serving as a member of the Environmental Audit committee.
Mr Caton was unavailable for comment at the time of going to press.