State Supreme Court Justice Thomas Farber said he would not release Colliton until he had imposed the sentence. The judge scheduled sentencing for Oct. 11.
Colliton, 43, admitted he had sex numerous times with one girl younger than 15 and another under 17 between Dec. 25, 2000, and March 1, 2005. He also admitted he visited a prostitute younger than 17 between August 2000 and February 2004.
Colliton's lawyer, Howard Greenberg, said his client faced 30 years in prison if he had been convicted at trial on a 43-count indictment that charged him with numerous counts of rape and sodomy.
Prosecutor Rachel Hochhauser said she was ready for trial but Colliton had agreed to "take responsibility for his actions" and plead guilty. She said the victims were told of the disposition of the case and "supported it."
Colliton, formerly of the prestigious Manhattan law firm Cravath, Swaine & Moore, fled the country in February 2006 after learning that police wanted to talk to him.
The 38-year-old mother, whose name was withheld to protect her daughters' identities, pleaded guilty in April 2006 to endangering the welfare of a child. She admitted she allowed her girls to have sex with Colliton and knew he was giving them money and gifts.