Blijburg is the largest and most beachlike city beach in Amsterdam. It has a sandy beach with a great view on the IJsselmeer lake. You can actually swim here, unlike many other city beaches in Amsterdam. It has a bohemian vibe, especially in the evening when the camp fire is lit. The beach bar and restaurant Blijburg is definitely worth a visit. They serve good food and often programme live music, DJ’s and other activities.
Amsterdam has other city beaches and of course the real beach at the coast: Zandvoort. This is traditionally the beach that most Amsterdam people go to, it takes only 25 minutes by train. It has endless sandy beaches and many trendy beach bars and restaurants. So if the weather is really sunny and you have the time, consider a day or just an evening at the coast.