Mackerel - Dun Laoghaire harbour

I'm looking for a spot to try catch some mackerel that is easy to get to from Dublin city without a car. Is the pier in DL worth a journey on the dart?
I'll take any other suggestions too.

Dun Laoghaire is a well known spot for mackerel fishing alright, Howth on the dart line as well but is always very busy this time of year. Another alternative is the South bull wall/ Poolbeg lighthouse, not far from the city centre but a hell of a walk down, if you have a bike you’d cycle down handy enough though.