Amazon's Canadian store features Wii U box art for Assassin's Creed 3, Avengers and Just Dance 4, reports IGN.
Nintendo Network logo also features.
Nintendo or Ubisoft is yet to officially unveil its Wii U cover art, and neither has commented on the leak.
The Wii U is scheduled to launch later this year. Reports have linked it with a November or December release.
Nintendo has suggested that the Wii U will be affordable when it launches, saying that its success will be determined by pricing, not hardware power or its launch date.
Ubisoft, meanwhile, will release seven titles during the Wii U launch period, making it the largest supporter of the console.
The firm's president Yves Guillemot said that despite the number of titles, the Wii U doesn't represent a "huge investment".
Watch Digital Spy's Wii U hands-on video below: