In an interview with the Jakarta Post newspaper, Andi Konggoasa, an Indonesian prosecutor, said Marco Archer Moreira, from Brazil, Namaona Dennis, from Malawi, and Muhammad Abdul Hafeez, from Pakistan, would face the firing squad at the beginning of June.
“We have prepared for the execution in co-ordination with relevant ministries, the embassies and the families,” he said.
The executions would be the first since 2008 in Indonesia where there are currently 25 foreigners on death row because of drugs offences.
Moreira was arrested in 2003 after attempting to smuggle around 30lbs of cocaine into Indonesia concealed in his paragliding equipment. An appeal for clemency in 2010 from Brazil failed to quash the death sentence.
Dennis and Hafeez were caught smuggling heroin in 2001. All three had appealed “to no avail”, Konggoasa said.
The announcement raises the pressure on Julian Ponder, Rachel Dougall, Paul Beales and Lindsay Sandiford who were arrested last month and have been accused of forming an “international” cocaine smuggling racket.
Ponder, Ms Dougall and Beales were arrested after Ms Sandiford was caught allegedly trying to import 11lb of cocaine into the country last month.
On Monday Indonesian police announced they had decided to hold the four Britons for another month of questioning.
Before their arrests, Ponder and Ms Dougall had shared a luxurious country villa on the island with their 6-year-old daughter. Speaking to the Daily Telegraph earlier this month, Ms Dougall claimed she had been “set up”.