The nuclear-powered subs were first spotted last week more than 12 miles off the U.S. coast of Georgia and have been heading north, the Canwest News Service reported.
Defense Ministry spokesman Dan Dugas said a long-range Aurora aircraft had been sent up to monitor the movements of the subs.
"Yes, the Aurora is on the watch as we enforce our sovereignty," he said. "We're watching to ensure we know what is happening along our coastlines."
Dugas said the submarines hadn't done anything that appeared threatening or evasive, and that the foray appeared to be "part of a pattern of Russia flexing its muscles," Canwest said.
On July 13, Russia fired two underwater long-range, nuclear-capable missiles in Arctic waters, and the state-owned RIA Novosti news agency reported the missiles each reached their targets near Russia's eastern border with Finland.