The beach in donabate is very clean with clear water, many people flock here during hot spells, parking can be limited at times of high numbers. A cliff walk is close by, which looks out to Lambay island. The scenery is natural and beautiful, even on a wild day, when the tide is high, crashing off the rocks. The village is 2km away, so gather supplies on your way through. There is a hotel right next to the beach, which serves up a nice meal 12 - 16euro, kids meals also available(and pints).
I have awarded this beach 4 stars, dropping 1 for parking on busy days..