Hon Yen

Hon Yen is a rock island a few hundred metres off the Phu Yen coast with a reef between it and the shore, and on a handful of days each year - the lowest spring tides, mostly in the months around April to July - the water drops far enough that the coral is exposed and can be walked among, which is what brings photographers and, increasingly, a problem: walking on live coral kills it, and the reef here has visibly deteriorated. Local authorities and conservation groups have been trying to manage that. Outside those tides it is snorkelled from the shore or simply looked at.

The landscape

• A reef exposed at the lowest tides - on a handful of days a year.
• Coral standing above water - which is what draws people.
• Visible damage from walking on it - the reef has deteriorated.
• A rock island offshore - Hon Yen itself.

When to go

April to July, timed precisely to the lowest tides. Half a day.

Things to know

Walking on the coral kills it, and the exposed-reef photographs that made the place known are the reason it is dying - looking rather than walking is the point. The tide window is a few hours on a few days. There are no facilities.

Nearby

Ganh Da Dia is north; Tuy Hoa is south.

Key facts