The 17-year-old boy, who cannot be identified for legal reasons, carried out the attacks as the women jogged or walked their dogs in Rodley on the morning of October 8.
Leeds Crown Court heard how he touched the bottom of a 48-year-old woman at around 8.15am, then tried to put his hand over the mouth of a 26-year-old woman a few minutes later.
The boy, who was 16 at the time, went on to grab a 40-year-old woman as she passed him on Alice’s Steps, which lead down from Leeds Ring Road.
He pulled her to the ground and the pair struggled until the woman managed to break free.
Judge Neil Clark said: “This is very serious offending. It was extremely frightening for your victims. You picked on lone women and went from one to the other until eventually you were frightened off.”
During police interviews the boy said he had been trying to steal the third victim’s phone.
But he was found guilty of two counts of sexual assault and one of attempted sexual assault during an earlier hearing at Leeds Youth Court.
Craig Sutcliffe, mitigating, said the incidents had been “extremely unpleasant” for the women but they had not been targeted for any specific reason.
He said the boy had suffered a trauma as a child and, although he could not remember it, had likely been a victim of abuse himself.
“My client has always admitted wrongdoing,” he said. “He is genuinely remorseful.”
He added the boy’s behaviour since the time of the assaults had been “exemplary”.
The court heard the boy was made subject to a youth referral order in September after a conviction for battery.
Judge Clark said the boy should be “utterly ashamed” of his actions which were “frankly disgusting”.
He said the boy’s criminal record, being under the influence of a substance at the time and the harm to victims were all aggravating factors.
But he said he must also note the personal circumstances.
Judge Clark said: “The most important thing I can do is to try to ensure you present no risk in future.”
The boy must complete a three-year youth rehabilitation order with supervision, a 20-day work programme and a six month curfew.
In addition, he was made the subject of an exclusion order banning him from part of the canal towpath, ordered to sign the sex offenders’ register for 30 months and must pay a £20 victim surcharge.
The judge also commended the bravery of the women, saying of the third victim: “Her bravery was remarkable. She must have been utterly terrified.”
He went on to say that she deserved recognition for her actions from the Crown Prosecution Service or police, as did the second victim.