Rina Cave lies thirty meters inland from the open Aegean, carved into the limestone cliffs of Kalandos on Naxos's southern coast. The cave's entrance sits at sea level, accessible only by boat or kayak when conditions allow. Geologists date the formation to the Pliocene, when tectonic uplift exposed the sedimentary layers that wind and wave have since hollowed into chambers. The name Rina derives from local usage; no formal archaeological survey has documented the site, though pottery shards suggest ancient fishermen used the recess for shelter. Today the cave draws visitors for its turquoise interior light, a function of depth and the white limestone substrate. Water clarity in the Kalandos area averages twelve meters in summer, and the cave's floor lies at four to six meters, creating the blue glow visible in midday sun. Tour operators from Agia Anna, Panermos, and Naxos Town include the cave in half-day and full-day itineraries that combine swimming stops, sail time, and island landings. The approach from the north passes the deserted islets of the Small Cyclades; from the south, the route follows the cliffs past Kalados and Alyko cedar forest. The surrounding coastline is protected under Greek coastal law, which restricts motorized access within fifty meters of the shore. Sailing catamarans and traditional caiques anchor offshore, and passengers transfer to dinghies or swim the final distance. Sea kayak tours depart from Agia Anna and Panermos, paddling the seven to nine kilometers along the coast. Morning departures capture the cave's best light; by afternoon, the sun moves west and the interior dims. Wind patterns shift in August, and operators cancel sailings when the meltemi exceeds force five. Rina Cave remains unmarked on most regional maps. No constructed path reaches it from land, and the nearest paved road terminates three kilometers inland at Kalandos village. The geological continuity of the Kalandos cliffs suggests similar formations exist farther east, but Rina is the only recess large enough to admit boats. The cave's ceiling rises eight meters at the deepest point, high enough for echo but low enough to block sky views once inside. Visitors report the temperature drop—Aegean water holds at twenty-three degrees in summer, while air outside reaches thirty-five.