These days Sandymount is becoming more popular with kiters. However, the launch areas at Sandymount are really only used around high tide and in easterlies. Otherwise Poolbeg is more flexible. It's a long walk at low water, but a large standing-depth area forms on an ebb tide. Depending on wind direction and strength, conditions vary from flat to chop to medium waves. There are more launch options down at 'Merion Gates', 'Booterstown Station' and the Martello Tower at 'Blackrock'. The further south you go, the more water you'll find at low tide.
Kite and Windsurfing Guide