Blue Grotto

Seven caves, one colour

The Blue Grotto (Taht il-Hnejja) is a system of seven sea caves in the cliffs of Malta's southern coast, near the village of Wied iz-Zurrieq. The main cave has a rock arch spanning approximately 30 metres and rising 15 metres, making it one of the largest sea caves in the Mediterranean basin.

Why the water glows

The water inside the caves has an intense, phosphorescent blue colour. The effect is created by sunlight reflecting off the pale sandy seabed and white limestone walls. Light entering through underwater openings is filtered — red and yellow wavelengths are absorbed while blue is reflected, producing a neon-like glow. The best conditions are in the morning (8:00-12:00), when the sun shines directly into the caves.

The boat trip

The caves are reached by small, traditional boats from the landing at Wied iz-Zurrieq. The trip takes about 25 minutes and passes through all seven caves. Boats do not operate in strong wind (swell enters the caves), so the attraction may be closed in winter and on windy days.

Practical tip: The boat trip costs EUR 8 (2026). Come before 10 AM for the best light and shorter queues. The viewpoint on the cliff above the caves is free and worth the visit on its own. Bus 74 from Valletta.