Beasley, a 32-year-old from California, escaped with another American, Paul Anthony Hoffman, 57. But the older man was caught shortly after the pair got over the wall, while Beasley remains at large, somewhere on the tourist island.
Still, investigators are trying to determine how Beasley got out undetected - and whether Kerobokan's guards played a role in his escape.
Beasley had been in the prison for four months, since officials caught him with a package that had 5.7 grams of hashish, according to Reuters.
His arrest is part of the Indonesian Government's crackdown on drug trafficking, which has sparked fears that the world's fourth-most populous nation is taking cues from Philippine President Rodrigo Duterte's violent drug war, marked by allegations of extrajudicial killings and human rights abuses.
"Be firm, especially to foreign drug dealers who enter the country and resist arrest," Indonesian President Joko Widodo instructed his law enforcement officers in July. "Shoot them because we indeed are in a narcotics emergency position now."
Drug-related arrests have swelled the nation's prisons, which are routinely understaffed and in poor condition, according to AP.
And many prisoners - including a few foreigners - have decided to risk an escape rather than remain in the facilities.
In June, four prisoners - an Australian, a Bulgarian, an Indian and a Malaysian - escaped from Kerobokan prison using a tunnel, according to the BBC. The quartet was arrested over a variety of drug charges. Two of them remain at large.
In July 2013, more than 240 prisoners - including a few terrorists - fled an Indonesian prison amid rioting at the facility, on the island of Sumatra, AP reported. In May, 440 prisoners sprinted out of a crowded prison (also on Sumatra) when they were let out of their cells for Friday Muslim prayers.
Paul Conibeer, a New Zealander who authored I Survived Kerobokan after spending several months there in 2013, said the prison was filled with too many inmates as well as corrupt guards who turned a blind eye to drug use and violence.
"I've seen people get murdered in there, I've seen people get bashed, I've seen drug overdoses, one guy died in my arms from sickness," Conibeer said, as reported by the Daily Mail.
"One of the things that really upsets me about it is that you get the death penalty for drugs and yet the place . . . is full of drugs."