Blue Cave

The Blue Cave (Plava špilja) is a sea cave on the Luštica Peninsula at the entrance to the Bay of Kotor, near Mamula Island (Herceg Novi Municipality, Montenegro). It’s famed for its vivid blue glow at midday and for safe swimming from boats when seas are calm.

• Chamber ~300 m² with a vault ~9 m above sea level – compact hall with placid water.
• Two entrances: a smaller one to the south and a main ~3×15 m opening SW – small boats enter in calm conditions.
• Inside depth ~4–5 m – pale limestone and sunlight create the intense azure effect.
• Best time is mid-day in summer (typically 10:30–14:00) when the sun is high.
• Commonly paired with Mamula Fortress, Our Lady of the Rocks and Yugoslav submarine tunnels.

• Blue-lit walls and “silver” water beneath the boat.
• Rugged Luštica coves and Rt Veslo on approach.
• Swimming and snorkeling inside the cave when allowed.

Wave action carved the cave in Luštica’s limestone. Boat trips became popular in the 20th century; today regulated entries ensure safety, with swimming permitted only when conditions allow.

Location: outer Bay of Kotor, Luštica; landmark Rt Veslo and Mamula; approx. 42.3739 N, 18.5960 E.
Getting there: by sea only – frequent tours and private boats from Herceg Novi, Kotor, Tivat and the marinas Luštica Bay/Portonovi/Porto Montenegro. Sea-kayak access from Rt Veslo is possible in calm weather.
Access: subject to swell and skipper’s decision; queues at the entrance in peak season.
When to visit: May–October; peak blue effect at summer midday.
Visit duration: 10–20 min inside; 1.5–3 h round trip from Herceg Novi and 3–4.5 h from Kotor.
Best time: June–September, clear skies and calm seas; for fewer crowds choose early morning or late afternoon.
Notes: low ceiling – stay seated; lifejackets and water shoes recommended; trips may be cancelled in rough seas; no facilities on site.