It is against the law for US bounty hunters to operate in Canada.
It doesn’t stop them from trying though.

I’ve watched “Dog, the Bounty Hunter” on A&E. It’s how it’s done in the US when someone skips bail. But it isn’t how it is done in Canada.

Bounty hunters are usually reserved for old Westerns and Star Wars films, not smalltown Ontario. But on the night of Nov. 14, just after Mr. Weckwerth had finished his moose and hamburger meatloaf dinner, the two men tracked him down and hauled him away in their silver van.

Mr. Weckwerth, a 60-year-old Eganville man, was wanted because he skipped out on a court hearing for drug-related charges in Ohio. He had lived in the U.S. for years, drifting around and never holding down a steady job.

He fled back to the Ottawa Valley, where he was known at area taverns in the summer as an amateur country singer.

The problem was, he had hired a private company — referred to in the U.S. as a bail bond company — to put up the money for his bond. Until he attended court, the government would keep the bond money and the bail bond company would be out thousands of dollars.

Enter the bounty hunters, also known as bail enforcement agents.

Now the two bounty hunters and Weckworth are in jail in Niagra Fall New York.

The bounty hunters face charges of forcible confinement and kidnapping and are being investigated by U.S officials for making false statements to a federal border agent.

In January 1988, an official document, called a memorandum of understanding, was sent between the U.S. State Department and Canada’s Foreign Affairs Department. It established that the kidnapping of persons by “so-called bounty hunters” was an extraditable offence.

Some faqs on the ‘profession’ here.