Is there a safer way to create a directory if it does not exist?

You can actually skip the if, even though Apple's docs say that the directory must not exist, that is only true if you are passing withIntermediateDirectories:NO

That puts it down to one call. The next step is to capture any errors:

NSError * error = nil;
[[NSFileManager defaultManager] createDirectoryAtPath:bundlePath
                          withIntermediateDirectories:YES
                                           attributes:nil
                                                error:&error];
if (error != nil) {
    NSLog(@"error creating directory: %@", error);
    //..
}

This will not result in an error if the directory already exists.

For Swift 3.0

do {
    try FileManager.default.createDirectory(atPath: folder, withIntermediateDirectories: true, attributes: nil)
} catch {
    print(error)
}

Swift 4.2

let fileManager = FileManager.default
let documentsURL =  fileManager.urls(for: .documentDirectory, in: .userDomainMask).first!

let imagesPath = documentsURL.appendingPathComponent("Images")
do
{
    try FileManager.default.createDirectory(atPath: imagesPath.path, withIntermediateDirectories: true, attributes: nil)
}
catch let error as NSError
{
    NSLog("Unable to create directory \(error.debugDescription)")
}

Swift 5.0

let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
let documentsDirectory = paths[0]
let docURL = URL(string: documentsDirectory)!
let dataPath = docURL.appendingPathComponent("MyFolder")
if !FileManager.default.fileExists(atPath: dataPath.absoluteString) {
    do {
        try FileManager.default.createDirectory(atPath: dataPath.absoluteString, withIntermediateDirectories: true, attributes: nil)
    } catch {
        print(error.localizedDescription);
    }
}