Fosso Bianco (Bagni San Filippo), Italy

What it is

Fosso Bianco is the milky, mineral-coated hot-spring stream just outside the village of Bagni San Filippo, in southern Tuscany between Val d'Orcia and the Amiata area. Over time, thermal water has built white limestone formations and small cascades, creating natural pockets where people soak.

The headline feature is the Balena Bianca (White Whale), a large white limestone mass formed by thermal sediments. The setting is shaded woodland, with warm water threading through pools and short drops. It is atmospheric, but it is also popular, so you may be sharing space closely, especially on weekends.

What makes it different

Compared with open, roadside springs, Fosso Bianco feels tucked away. The forest keeps it cooler on hot days, and the white rock makes the water look pale and opaque. Conditions shift season to season because rainwater and thermal flow mix, so the exact look and the best pools can change, especially in winter.

Where it is

Bagni San Filippo is a small thermal village in Tuscany, not far from Monte Amiata. The soaking area is reached on foot from the village via a path into the woods. Visit Tuscany describes the route as an evocative footpath leading to the Balena Bianca area and nearby pools.

Getting there

Arrive by car and use village parking, then walk in. The approach is short, but it can be muddy after rain, and wet rock starts appearing quickly. The streambed is uneven, so plan on stepping in and out of shallow water and over mineral crust.

Bring water shoes with grip, a towel, drinking water, and something small to carry your essentials. In cooler months, you will want a warm layer for the walk back through the trees. Expect more visitors on weekends and holidays, so if you want space, aim for early morning or a weekday.

Important: Visit Tuscany notes that the Balena Bianca formation is delicate and that it is forbidden to touch it, walk on it, or bathe near it. Treat that area as a look-only feature and choose one of the other pools for soaking.

Who it suits

This is best for travelers who like natural settings and do not mind a little mess, wet feet, and variable conditions. It is also a good stop if you care about the geology, the white mineral deposits are the whole point. If you want showers, controlled water temperatures, and calm personal space, this will feel chaotic.

I would not call it an easy family soak. Older kids who can move carefully and follow instructions can enjoy it, but the uneven surfaces and hot spots close to the source are not ideal for toddlers. Crowd levels can also make it hard to supervise.

Mobility realities

There is no verified wheelchair access at Fosso Bianco. The route involves a dirt path, steps in places, and wet, irregular rock at the pools. If you have limited balance, this is the kind of place where a short slip can ruin your day. Consider visiting for photos from safe edges rather than committing to a soak.

Expect basic, wild conditions. There are no guaranteed changing facilities at the pools, so many visitors change in town and walk in dressed for the water.

On-site hazards

The biggest issues are slippery mineral crust, hidden dips, and water that is hottest near the source. Move slowly, keep footwear on, and avoid sitting directly under small falls where the rock is polished and slick. If the stream is running higher after rain, currents can be stronger than they look in shallow channels.

Respect the protected area around Balena Bianca. The formation is fragile, and the guidance to not touch or bathe near it is there for a reason. Choose established soaking pools downstream and keep your hands off the bright white surfaces.

Etiquette

Keep soap, shampoo, and oils out of the water. Pack out all trash, including tissues and wet wipes. Keep voices down, sound carries in the wooded channel, and people come here for a quiet soak even when it is busy.

Do not block narrow passages where water flows between pools, and avoid leaving bags on the only dry stepping points. If you are taking photos, be quick and mindful of other visitors in the frame. In summer, arrive early if you want a calmer experience, midday crowds can feel more like a queue than a soak.

Is Fosso Bianco free to visit?

The thermal pools are described by Visit Tuscany as free thermal pools where you can bathe. Conditions and access can change with weather.

Can I soak at Balena Bianca?

Visit Tuscany says it is forbidden to touch it, walk on it, or bathe near it. Look, take a photo, and use other pools nearby for soaking.

What should I wear?

A swimsuit is the safest assumption for a public, mixed-use site. Bring a towel and water shoes with grip.

Does the area change seasonally?

Yes. Visit Tuscany notes that water amount and the path to the waterfall can change frequently, especially in winter when rainwater mixes with the thermal flow.