When you walk into the water the current can be a bit strong or the waves are around 1m. To avoid this the advise is to drag out of the first waves. Behind that the water is mainly flat.
Long, sandy beach. Some parts wider, some parts more narrow. It's best to start on the right side of the beach (if you look to the sea). As on the left side there is a peer and also the beach for locals. As they also enjoy the water it's best to go to the right side and start in front of the Blue Ocean hotel.
In Negombo is plenty of nightlife, pool bars and good restaurants especially on Ethukala road. Besides an outside club next to the Oasis Hotel, pubs such as Sherryland are good places to hang out. Local people also go to these places. For the big clubs and nightlife you have to go to Colombo.