Yonaguni

Yonaguni is 111 kilometres from Taiwan and the westernmost inhabited point of Japan, about ten kilometres long, with cliffs on the south side, small semi-wild Yonaguni horses grazing the headlands, and a population under two thousand. Divers come for two things. From December to March, schools of scalloped hammerhead sharks gather off the island in numbers that make it one of the few reliable places in the world to see them - in cold rough water, on advanced dives. The other is the Yonaguni monument: a mass of stepped sandstone about twenty-five metres down, discovered in 1986, whose flat faces and right angles led to claims of a sunken structure. The scientific consensus is that it is natural, produced by the bedding and fracture pattern of the sandstone, though a minority argue otherwise; it is dived either way.

What you actually see

• Hammerhead season - schooling scalloped hammerheads from December to March.
• The monument - stepped sandstone at twenty-five metres, natural by scientific consensus.
• Yonaguni horses - small semi-wild native horses grazing the headlands.
• The western edge - the last inhabited point of Japan, 111 kilometres from Taiwan.

When to go

December to March for hammerheads; April to October for calmer diving. Three days.

Honest expectations

Hammerhead dives are in cold rough water and are for experienced divers only. Flights and the ferry are cancelled in weather and can strand visitors for days. The monument is natural according to the weight of evidence - expectations set by documentaries will not survive. Facilities on the island are minimal.

Nearby

Ishigaki is east by air; Iriomote lies between them.