Xcode 8 • Swift 3
if let audioUrl = URL(string: "http://freetone.org/ring/stan/iPhone_5-Alarm.mp3") { // then lets create your document folder url let documentsDirectoryURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first! // lets create your destination file url let destinationUrl = documentsDirectoryURL.appendingPathComponent(audioUrl.lastPathComponent) print(destinationUrl) // to check if it exists before downloading it if FileManager.default.fileExists(atPath: destinationUrl.path) { print("The file already exists at path") // if the file doesn't exist } else { // you can use NSURLSession.sharedSession to download the data asynchronously URLSession.shared.downloadTask(with: audioUrl) { location, response, error in guard let location = location, error == nil else { return } do { // after downloading your file you need to move it to your destination url try FileManager.default.moveItem(at: location, to: destinationUrl) print("File moved to documents folder") } catch { print(error) } }.resume() } }