In Zeeland there are two main areas for diving; the 'Oosterschelde' and the 'Grevelingen'. The 'Oosterschelde' is connected to the North Sea and has tidal currents. The best opportunity to dive is the time frame between the tides (called 'slack' tide).To help plan your dive at the right moment, special tide tables are available at the dive centers in Zeeland. In the 'Grevelingen' diving is not tide-dependent. The connection to the North Sea is closed with a flood-gate, only to let fresh saltwater penetrate occasionally into the 'Grevelingen'.