Paul McGrath, 67, sexually assaulted a woman in the bus stop outside the Admiral Napier Pub, on Cowbridge Road East, at around 1am on Friday, April 14.
Detectives have praised the actions of some members of the public – including a group of young men from Splott – who intervened.
McGrath, from Riverside, was arrested at the scene and later pleaded guilty to two counts of sexual assault by touching.
The court heard that McGrath had targeted the victim who was intoxicated and vulnerable, and that his actions had caused her extreme psychological harm.
She was unconscious during the 22-minute ordeal which was captured on CCTV.
Detective Constable Joe Davies from South Wales Police said: “Everyone has the right to feel safe and our immediate response on April 14 meant McGarth was arrested at the scene.
“We would like to thank those members of public who stopped to intervene and responded to a public appeal for information.
“The strength of the evidence resulted in guilty pleas and thankfully meant the victim did not have to give evidence in court.”
McGrath, who has been in custody since his arrest, was sentenced at Cardiff Crown Court on Tuesday, November 14 to 25 months in prison for each of the two offences to run concurrently.
He is on the Sex Offenders’ Register for 10 years and is also subject to a lifelong restraining order, banning him from contacting the victim directly or indirectly,
DC Davies added: “The restraining order was so important to the victim who, after sentencing, described how it will give her the ability to move on with her life. We wish her well with her continued recovery.”
