Swift tab bar view prepareforsegue
Have you checked whether the prepareForSegue in your TabBarController ever gets called?
It would never be called since the connection between a UITabBarController and its children view controllers isn't a storyboard segue. You should get a reference directly to the viewController from the UITabBarController by accessing its viewControllers collection at the index you want.
var tabBarController = segue.destination as UITabBarControllervar destinationViewController = tabBarController.viewControllers[0] as YourViewController // or whatever tab index you're trying to accessdestination.property = "some value"