o visit the Kornati and not see the submarine world... Qualified autonomous divers are in a privileged position: they can enjoy all the things that are the reason why this place is a national park.
We recommend to others, without diving qualifications, that they take a diving mask and snorkel, and then take a peek into the blue deeps of the clear Kornati waters. You can see a lot of memorable things, even from the surface. You don't need a licence for snorkelling (diving without autonomous diving equipment). However, a diving expedition with scuba gear can be done only in organised and approved groups, and only if organised by a person or an agency authorised for such activities. The person or the agency must have a contract to organise and guide diving groups with the Kornati National Park.
It is not allowed to touch anything or take out of the sea (except if you find garbage). It is prohibited to intentionally disturb or endanger sea organisms. Night diving (between 19:00 and 7:00) is not allowed. Beside their diving knife, divers must not have weapons or tools, either with themselves or on the boat. Divers have to respect all the laws and regulations of the Republic of Croatia that apply to underwater activities. The greatest depth allowed for diving in the Kornati National Park is 40 metres.
- from www.np-kornati.hr