Watkins, along with his two co-defendants ‘Woman A’ and ‘Woman B’, stood emotionless in the dock as their sentences were handed down.
The mothers of the abused children also pleaded guilty to child abuse charges at a hearing in November along with the musician.
The judge, Justice Royce, told the courtroom evidence in the case “breaks new ground” and “plunged into new depths of depravity”, while Watkins was “noticeably shaking” as he stood.
The court was told Watkins poses a “significant risk” to young women and children and was informed he had told a probation officer he did not know what lengths he would have gone to with children had he not been arrested.
Watkins will spend 29 years in jail and a further six years on license being monitored by police.
The 36-year-old frontman was sentenced alongside two women, the mothers of the abused children known as ‘Woman A’ and ‘Woman B’, who also pleaded guilty to child abuse charges at a hearing in November with Watkins.
‘Woman A’ has been sentenced to 14 years in jail, while ‘Woman B’ has been jailed for 17 years.
A phone call made from prison revealed Watkins had planned to make a statement saying his admission of sex offences was “mega lolz” and that he wasn’t a paedophile and only pleaded guilty to avoid a trial.
In it, he told a female friend: “I’m going to put a statement on the 18th now just to say it was mega lolz, I don’t know what everyone is getting so freaked out about.”
The phrase was used by the Lostprophets on some of their T-shirts and they also performed in front of a back-drop saying ‘MEGA LOLZ!’ on the main stage of the Reading Festival in 2010.
The disgraced rocker also told the woman, named Samantha, that his evil crimes were “not that bad” and said he had considered trying to trick a jury into believing he was innocent using his “charm”.
He told her: “It was like either me go up there and say come on it wasn’t that bad. Do I try to win them over with my charm? Or do I just make things worse for myself saying I was off my head, I can’t remember.”