The Blue Cave lies half-submerged beneath the Luštica Peninsula, its entrance a jagged arch carved by millennia of wave action into pale limestone. Sunlight refracts through the water column at precisely the angle required to turn the cavern's interior an electric cobalt — a phenomenon visible only when the sea is calm and the sun high. Geologists trace the cave's formation to the Cretaceous, when tectonic shifts lifted the seabed and left behind a honeycomb of karst chambers. The adjacent submarine tunnels, by contrast, are Second World War relics: concrete-lined passages built by the Yugoslav Navy to shelter torpedo boats from aerial reconnaissance. Today both sites anchor a triangle of speedboat routes that depart from Perast, loop past Our Lady of the Rocks, and return via the Verige Strait. A kotor blue cave private tour emerged as a distinct category in the mid-2010s, when operators began offering bespoke charters separate from the crowded ferry circuits. The shift was driven by demand from travelers seeking swim stops inside the cave itself — an impossibility on fixed-schedule group boats, which idle at the mouth for photographs but never drop anchor. Private vessels, typically six-meter rigid inflatables with 115-horsepower outboards, can nose into the shallows and cut engines, allowing passengers to slip overboard into water that holds its luminous blue even in shadow. The submarine tunnels require a similar approach: their low ceilings and narrow berths admit only small craft piloted by captains familiar with the tide tables. Our Lady of the Rocks serves as the navigational midpoint for most routes. The artificial islet, constructed atop a submerged reef through five centuries of deliberate rock-sinking by Perast sailors, anchors the bay's eastern approaches. Speedboat itineraries treat it as a docking waypoint rather than a destination — passengers disembark for the fifteen-minute church visit, then re-board for the onward leg to the cave. The arrangement reflects the logistics of Boka Bay itself: distances are short, currents predictable, and the limestone coast riddled with enough inlets to shelter a dozen simultaneous tours without overlap. By summer 2026, private charters account for nearly a third of all Blue Cave visits, a figure that climbs to half during July and August when the shared boats run at capacity.