Check URL loaded in a WebView

You need to make your View Controller conform to the UIWebViewDelegate protocol

First add UIWebViewDelegate to the view controller that contains your uiwebview

class ViewController: UIViewController, UIWebViewDelegate {

Connect your webview to your view controller

@IBOutlet weak var webView: UIWebView!

Add the shouldStartLoadWithRequest method inside the webview view controller:

func webView(webView: UIWebView, shouldStartLoadWithRequest request: NSURLRequest, navigationType: UIWebViewNavigationType) -> Bool {
    print("shouldStartLoadWithRequest")
    if let newURL = request.URL {
       print(newURL.absoluteString)
    }
    return true   // para que a nova url seja carregada retorne 'true' ou se voce quiser bloquear retorne 'false'
}

Do not forget to define that your view controller is the webview delegate, just add webView.delegate = self in the viewDidLoad method:

webView.delegate = self

demo project

import UIKit

class ViewController: UIViewController, UIWebViewDelegate {

    @IBOutlet weak var webView: UIWebView!

    override func viewDidLoad() {
        super.viewDidLoad()
        webView.delegate = self
        guard let googleURL = NSURL(string: "https://www.google.com/") else { return }
        webView.loadRequest( NSURLRequest(URL: googleURL) )
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

    func webView(webView: UIWebView, shouldStartLoadWithRequest request: NSURLRequest, navigationType: UIWebViewNavigationType) -> Bool {
        if let newURL = request.URL {
           print(newURL.absoluteString)
        }
        return true
    }
}