Traditional New Year's dive is basically thousands of people getting a swim in a freezingly cold water anywhere around them. Since these things tend to get commercialized, the chilling plunge is an organized activity managed by a big soup brand.
If you are lucky, you can taste hot chocolate or Dutch pea soup afterwards. It is a lot of fun! On average, 10,000 people take a swim this day on the beach of Scheveningen! If you want some place less crowded go for another location out of 60 possible around the Netherlands.
For more details and the latest updates, please check with the official website (see External Resources below.) Also, take a look at the map suggesting the best accommodations nearby.