Can Someone Listen to, or Read, Your Private Communications? 

In most circumstances it is an offence under the Criminal Code of Canada to intentionally intercept a private communication, unless at least one party to the conversation consents. The maximum prison term upon conviction is five years. See Part VI of the Criminal Code of Canada.

It is also an offence to disclose private communications and to possess equipment for the purpose of intercepting private communications except if it is permitted by a superior court judge for law enforcement purposes. A private communication includes a communication by telephone, internet, or other technology.

In certain limited situations, intercepting private communications is allowed.  For example, a telephone or internet service provider is allowed to intercept private communications for the purposes of providing service, for quality control, managing the system or protecting against harm to the system. 

Police may intercept a private communication without a warrant if there is an urgent risk of bodily harm. In any other situation, police or intelligence agents need a warrant and must go to a judge, and give specific information to enable the judge to exercise her discretion to set limits on the privacy intrusion permitted under the warrant.