They have missed a year of their courses as a result, but have narrowly escaped being jailed after pleading guilty at Warwick Crown Court to their parts in the robbery.
Gihan Gamage, 20 of Moorhouse Close in Wellington; Ghinal Leitan, 21, of Elm Road, Earlsdon, Coventry and Manul Desilva, 21, of Sussex Close, Slough, were sentenced to two years in prison suspended for 12 months.
All three were also ordered by Judge Sylvia de Bertodano to carry out 180 hours of unpaid work and to pay £600 compensation each to their victim within 28 days.
Lee Marklew, prosecuting, said that at just after midnight on November 1 a final year student was walking home from Coventry University library where he had been studying when he was attacked from behind by Gamage.
He was grabbed in a headlock before being thrown to the floor and ordered to hand over his iPhone.
The frightened student did as he was told and one of the three, who had all covered their lower faces, demanded the password.
The victim was then pulled to his feet and was being frogmarched along the road towards some bushes when a woman who had seen what happened asked if he was OK and said she was calling the police.
One of the three had taken his rucksack, which the victim managed to grab back before they made off and the woman phoned the police.
With the help of CCTV cameras, they were stopped in a nearby street and arrested.
When they were interviewed they at first denied being involved in the robbery, but after being shown CCTV footage Gamage admitted he was the one who had thrown their victim to the ground.
Gamage, an architectural student at the university, said that afterwards they struggled to come to terms with what they had just done and had smashed the phone and thrown it way.
Leitan said he was the one who had asked for the password and pulled their victim to his feet, planning to take him into nearby bushes out of sight.
He added that he had had to buy a new phone and, worried about walking home late at night, had had to spend more than £100 on taxis since the robbery.
Piers Mostyn, for Leitan and Gamage, said: “This is a tragic example of three otherwise well-meaning young men who did something very out of character in a spontaneous moment.
“What comes through with Mr Gamage is the deep shame he feels. Mr Leitan is described as being very remorseful. He is in his final year, doing computer studies.”
Mr Mostyn said the university had suspended all three, and they will have to re-apply to continue with their courses next year, either at Coventry or another university.
Michael Epstein, for Desilva, who was studying business administration, said: “He, like his co-defendants, fully accepts his responsibility for what was a horrific moment of stupidity.
“Everyone has been searching for an explanation of how three students of good character and from good families have behaved in this way. It’s likely to have been a thrill-seeking incident. It was a rare moment of stupidity.”
Sentencing the three, Judge de Bertodano told them: “It is absolutely terrifying to be set upon in the street late at night by three people you do not know who have got their faces covered.
"He didn’t know you are all otherwise respectable young students, you could have been anyone.
“When I read these papers it was absolutely clear to me I was going to be sending the three of you out of the door at the back and to prison. But I can just avoid doing that.”