The men's lawyer, Salah al-Hejailan, said they left Saudi Arabia on Friday immediately after being granted clemency.
The releases are being seen as a tacit admission by the Saudi authorities that they fingered the wrong people.
Two of the men had been sentenced to death and faced public beheading.
The others were given lengthy prison sentences.
They were accused of carrying out several bombings in Saudi Arabia, including an attack which killed Briton Christopher Rodway.
Saudi authorities blamed the bombings on a turf war over illegal but lucrative alcohol sales.
But families of the jailed men said Saudi Islamic groups were responsible for the attacks.
"The grant of clemency is even more remarkable considering the severity of the punishments all the accused were facing," Hejailan said.
The four Britons facing lengthy jail terms were James Patrick Lee, Les Walker, James Cottle and Peter Brandon.
A seventh man, Briton Glenn Ballard, was also released on Friday after being detained for 10 months but not charged.
Thirty five people were killed in May in an attack on a Riyadh compound
He had been a witness against the others and could have been held until the sentences against them were ratified.
Two of the accused - Briton Alexander "Sandy" Mitchell and Canadian William Sampson - were shown on television confessing to the attacks.
They later retracted their confessions and their families and friends said they believed the men were tortured.
Hejailan dismissed the official explanation for the bombings, saying alcohol sales would have earned the men only a few thousand dollars a year and "could not possibly be a rationale for these crimes".
He added: "Five of the detainees have insisted all along on the retraction of their early televised confessions and have refused any plea bargain to admit guilt for the sake of early deportation."
Analysts have linked the violence, which continued after the men were detained, to anti-Western dissidents in Saudi Arabia.
In the biggest attack yet, 35 people were killed when Western compounds in Riyadh were struck in May.
Saudi Arabia has launched a crackdown against Islamic groups during the past few years.