No, tickets cannot be purchased on site because there is no entrance fee. It is a publicly accessible, informal location, not a commercial attraction.
The 'Hidden Groningen Beach' is an open, informal bathing and leisure spot, not a managed attraction. Therefore, there are no tickets required or sold to access the area. Visitors can freely walk onto the sandy section and enjoy the lake. There is no gate, no ticket booth, and no staff managing entrance.
This informal status means that visitors should not expect any commercial services like kiosks or vendors selling items on site. Any refreshments or necessities must be brought by the visitor.