A British holidaymaker died of her injuries having fallen down a well in a restricted area at the Arade dam near Silves.
The tourist entered a fenced-off area so as to take a better photograph and stood on a metal well covering which gave way.
Her husband and two friends saw the accident and immediately summoned help.
An emergency team used specialist hoist equipment to lower two men down the well to attempt to revive the woman but she was found to be dead.
The Briton’s body was removed from the bottom of the well 10 metres below ground, as firefighters, paramedics and police attended the scene.
The tourist was on holiday in Albufeira with her husband and two friends and had decided to visit Silves and then the picturesque dam.
A Foreign Office spokesman commented “We are aware of the death of a British national on June 12 in the Algarve in Portugal. We are providing consular assistance to the family,” but has not yet released the name of the woman, reportedly in her 60s.