SWIFT 4:
1. Create an @IBAction with segue inside controller you want to unwind to:
@IBAction func unwindToVC(segue: UIStoryboardSegue) {
}
2. In the storyboard, from the controller you want to segue (unwind) from ctrl+drag from the controller sign to exit sign and choose method you created earlier:
3. Now you can notice that in document outline you have new line with title "Unwind segue....". Now you should click on this line and open attribute inspector to set identifier (in my case unwindSegueIdentifier).
4. You're almost done! Now you need to open view controller you wish to unwind from and create some method that will perform segue. For example you can add button, connect it with code with @IBAction, after that inside this IBAction add perfromSegue(withIdentifier:sender:) method:
@IBAction func unwindToSomeVCWithSegue(_ sender: UIButton) {
performSegue(withIdentifier: "unwindSegueIdentifier", sender: nil)
}
So that is all you have to do!