THREE BLUES
Blue Cave vs Green Cave vs Blue Lagoon
Three glowing places on the same day trip, constantly confused — which is which, and where you can actually swim.
See Blue Cave day trips on GetYourGuide ↗The Blue Cave (Biševo)
The famous one: a sea cave on Biševo that glows electric blue around midday, entered by a small local boat through a low opening for a short circuit. You don't swim here, there's a separate cash entrance fee, and it's the most weather-sensitive stop of the day. When people say 'the Blue Cave', this — Modra špilja on Biševo — is what they mean, and it's the stop everything else is timed around.
The Green Cave (Ravnik)
A different sea cave entirely, on the islet of Ravnik, lit green through a hole in its ceiling rather than blue from below. Its entrances are large enough to sail into, and — crucially — you can swim and snorkel here, in clear, green-lit water. If the Blue Cave is the one you look at, the Green Cave is the one you get into. It isn't a stop on the tour we link to, so look for a Vis trip that lists Ravnik if it matters to you.
The Blue Lagoon (Budikovac)
Not a cave at all: a shallow, sheltered turquoise lagoon between the Budikovac islets, where a pale sandy floor throws the light back blue-green. It's the day's easy swim — warm, calm, clear, often with more than twenty metres of visibility — and there's a small seasonal restaurant on the island. Confusingly, some shorter Split boat trips are branded 'Blue Lagoon' after this spot and never go near the Blue Cave, which is where a lot of booking mistakes begin.
Getting the booking right
The practical upshot: if you want the glowing Blue Cave, book a five-island tour that lists Biševo, and you'll get Komiža and the Budikovac lagoon along the way as your swim stops. If you book a 'Blue Lagoon' three-island trip instead, you'll get a lovely swim at Budikovac but no Blue Cave. Read the stop list, look specifically for Biševo, and you'll end up on the right boat.