Laganas Bay shelters the Mediterranean's densest nesting population of Caretta caretta, the loggerhead sea turtle — a species whose females return to the same Zakynthian beaches where they hatched decades earlier. Established in 1999, the National Marine Park of Zakynthos protects 135 square kilometers of coastal waters and six nesting beaches, enforcing speed limits for vessels and seasonal mooring restrictions to safeguard egg-laying sites. Each summer between May and October, female loggerheads drag themselves ashore under cover of darkness to excavate flask-shaped chambers in the sand, depositing clutches of 80 to 120 eggs before returning to the sea. Hatchlings emerge roughly eight weeks later, typically at dawn, navigating toward the horizon's brightest glow — a journey fraught with predation and disorientation from artificial lights. Zakynthos turtle boat tours operate under strict park guidelines, maintaining minimum distances from swimming turtles and idling engines when animals surface to breathe. Speedboat excursions circle Marathonisi — locally called Turtle Island for its carapace-like silhouette — where shallow seagrass meadows serve as foraging grounds. Glass-bottom vessels allow observation without hull noise, their transparent panels revealing juveniles grazing on Posidonia beds three meters below. Operators coordinate with park rangers to report sightings and injured animals, contributing to ongoing population monitoring. Morning departures between 09:00 and 11:00 yield the highest encounter rates, as loggerheads bask near the surface during calm conditions, their mottled shells visible against cobalt water. The marine park's boundaries extend to the Keri Caves, a chain of sea-carved grottoes along Zakynthos's southwestern cliffs. Millennia of wave action have hollowed limestone into cathedral-scale chambers, their ceilings dripping with calcite formations. Tour itineraries often combine turtle spotting with cave exploration, threading narrow passages where sunlight refracts through submerged openings, painting turquoise gradients on rock walls. At Myzithres, two bone-white islets rise 30 meters from the seabed, remnants of a collapsed cliff face now colonized by Eleonora's falcons. Conservation fees fund beach patrols and nest protection, ensuring Zakynthos remains one of seven key Mediterranean sites where loggerhead populations are stabilizing after decades of decline.