Formiche di Grosseto lighthouse

The Formiche di Grosseto lighthouse rises from a bare rock off the Maremma coast, in the province of Grosseto, Tuscany. It marks one of the most isolated corners of the Tuscan Archipelago, a spot with no roads leading to it — the only way in is by boat.

What exactly is this place?

Formiche di Grosseto is a small group of three islets: Formica Grande, Formica Media and Formichino. They shoot up almost vertically from a seabed roughly 100 metres below, which is part of why the sight is striking from a boat — a sliver of rock breaking the surface of open sea. Formica Media is little more than a narrow strip of stone, and Formichino is really two smaller skerries. Only the largest of the three, Formica Grande, carries anything beyond bare rock: the lighthouse itself.

What's the story behind the lighthouse?

The lighthouse on Formica Grande dates back to 1901, when it was put into service by the Italian Navy (Marina Militare) as a navigation marker for ships passing along the Maremma coast. It now runs fully automatically on solar power, flashing white every 6 seconds and visible from up to 11 nautical miles away. It remains a working aid to navigation rather than a heritage site open for visits — its purpose has always been purely functional.

How do you actually get there?

There's no bridge, scheduled ferry or road to the islets — the only way to reach them is by sea, either with your own boat or on an organised trip, usually a diving excursion. Porto Santo Stefano on Monte Argentario is a common departure point, roughly 15 nautical miles away, while setting off from the Maremma coast near the mouth of the Ombrone river shortens the crossing to around 9 nautical miles. In practice, that means looking for a local boat operator or dive centre running trips out to the islets — there's no public transport link of any kind.

What's worth seeing?

The real draw isn't the lighthouse itself but what lies beneath the surface around it. The waters here are known for their clarity and rich marine life, and the seabed holds shipwrecks and archaeological remains that have drawn divers for decades. That makes Formiche di Grosseto a destination mainly for diving and boating trips rather than conventional sightseeing — the islets themselves have no tourist facilities, beaches or services.

When's the best time to visit?

Summer is generally the best window for a trip out here, with calmer seas and clearer underwater visibility making diving conditions more favourable. Outside the summer months, open-sea conditions can turn rougher, which is why most operators concentrate their excursions to Formiche di Grosseto in the warmer part of the year.

Frequently Asked Questions

Can you land on the islet with the lighthouse? Access to Formica Grande is limited — it's primarily an active navigation installation rather than a tourist site, and landing depends on sea conditions and any restrictions in place.

How do you reach Formiche di Grosseto without your own boat? The easiest option is booking a boat trip or diving excursion with a local operator working out of Porto Santo Stefano or the Maremma coast.

Is diving possible around the islets? Yes — it's one of the main reasons people come here. Clear water, abundant marine life and underwater wrecks draw divers from across Tuscany.

How far are the islets from the mainland? About 15 nautical miles from Porto Santo Stefano on Monte Argentario, and around 9 nautical miles from the mouth of the Ombrone river.