I also need this functionality and have requested it in FB19932104

I actually figured it out - it appears that it isn't just included in UIKit, but is instead part of an extension in HealthKitUI. Fixed by adding import HealthKitUI

I have a Catalyst-enabled app with a UITabBarController for view switching and a custom "tab bar" (actually a UICollectionView). In my case, I wanted to hide this new tab bar and side bar. Here is the workaround I needed to do to accomplish that, as setTabBarHidden didn't work for me. Posting here in case it helps anyone else. internal class MainTabBarController: UITabBarController { internal override func viewDidLoad() { #if targetEnvironment(macCatalyst) mode = .tabSidebar sidebar.isHidden = true #else setTabBarHidden(true, animated: false) #endif } }