San Juan is a speck on the high, dry southwestern edge of Bolivia, where the Altiplano turns into a landscape of salt, volcanic rock and sky. It lies south of Uyuni, on the route that heads toward Laguna Colorada and the Chilean border, and there is no larger town anywhere nearby, only a handful of houses, a few simple lodgings, some llama pens and miles of empty plateau. The height is well over 3,600 metres, so the air is thin, cold and very clear.
The riding here is expedition riding, not touring. The roads are mostly gravel, sand and corrugated tracks, with wash-outs, soft patches and crossings of dry streambeds, and they are often unmarked, so a GPS track and a companion are wise. Strong wind blows almost daily in the afternoon, raising dust and making progress slow. The nights are bitter, with temperatures well below freezing even in the dry season, and the middle of the day can be warm in the sun. The best time is the dry season, roughly May to October, but the cold is serious, and the rainy season, from December to March, can flood the salt and cut the tracks.
Fuel is a real planning issue. There are no reliable fuel stations out here, and riders carry spare fuel from Uyuni, where supplies and mechanics are found. Bring water, food, tools and a satellite messenger if you have one, because mobile coverage is absent and help is hours away. Tour operators run jeeps along these tracks, so you may meet them at lodgings, and they are a useful source of news about conditions.
The surroundings are astonishing. Volcanoes rise above the plateau, some of them steaming, with colours of rust, ochre and purple in the bare rock, while salt flats glimmer white in the distance. Vicunas, the wild relatives of the llama, graze in small groups, and flamingos feed in the lagoons farther south, their pink feathers brilliant against the grey-blue water. The air smells of dust and cold stone, and at night the stars are almost too many.
The people here are Quechua and Aymara herders and miners, and life is hard. Quinoa grows on the high plain, and llama meat is the main fare. Be polite, ask before taking photographs and carry small change for purchases.