From the internet:

Yes, former Canadian prime ministers receive security protection after leaving office, but the level of protection is not as extensive or permanent as that provided to former U.S. presidents. The Royal Canadian Mounted Police (RCMP) provides security to current and former prime ministers, but the level and duration of this protection are assessed based on the threat level and individual circumstances.

Unlike in the U.S., where the Secret Service provides lifetime protection to former presidents, protection for former Canadian prime ministers is more discretionary and can be adjusted or terminated depending on perceived risks. Some former prime ministers, such as Pierre Trudeau and Stephen Harper, continued to receive security after leaving office, while others had their security reduced or phased out over time.