Offenders who are admitted to a Correctional Service of Canada institution are assessed as soon as they arrive. If they're a sexual offender, they are recommended for either a low-risk, moderate-risk, or a high-risk program. That becomes part of their correctional plan, which is now mandatory. That factors into the consideration, of course, when they are considered for parole or for day parole.
Also, some offenders will have a long-term supervision order at the time of sentencing, if the view of the judge is that this particular individual may pose a risk or may not be as open to some treatment options and programs as other offenders might be.
As well, if they still pose a risk upon release, they can also have a section 810 peace bond imposed on them, as any individual can. It doesn't have to be an offender necessarily.