U.S. revives Cold War submarine spy program to counter China

On a windswept island 50 miles north of Seattle sits a U.S. Navy monitoring station. For years, it was kept busy tracking whale movements and measuring rising sea temperatures. Last October, the Navy gave the unit a new name that better reflects its current mission: Theater Undersea Surveillance Command.

The renaming of the spy station at the Whidbey Island facility is a nod to a much larger U.S. military project, according to three people with direct knowledge of the plans: conducting the biggest reconstruction of America’s anti-submarine spy program since...