The National Marine Park of Zakynthos protects Laganas Bay, the southern beaches, and the small islands and waters used by loggerhead sea turtles. It is not a fenced attraction so much as a protected landscape overlaid on one of the island's busiest holiday zones.
From Argassi, the easiest way to understand the park is to visit Kalamaki or take a regulated boat trip into the bay. Do not expect guaranteed turtle sightings, and avoid operators that crowd or chase wildlife. The best part of the park is the reminder that these beaches are not just holiday infrastructure; they are also working nesting habitat.