How to change skin to Batman Beyond?

I've finished Batman Arkham City (now with 63% complete yet), and I still don't have any option to change the skin.

How can I change my default Batman skin to Batman Beyond (or other skins) ?

Solution 1:

Before completing the game, you can only change skins in the challenge rooms, after completing the game you have the chance to pick your Batman skin before loading your normal game or new game plus.

Edit: You can change skins before completing the game by entering this cheat code, I don't know if disables achievements/trophies or not, though

Press the following combination on the Main Menu screen (after you have selected your save slot):

• Left, Left, Down, Down, Left, Left, Right, Up, Up, Down

Solution 2:

You need to have the skin's DLC first of all (it doesn't come with the game by default). If you don't have that yet, the cheapest/easiest way you can get one is through Nos's rewards program (google it). If you can't find any Nos near you, you could also buy one on eBay for a few bucks.

Assuming you have the DLC downloaded and installed, ...

According to a post on some forums, you need to go to where you select New Game Plus and press A.

Solution 3:

You can't buy the Batman Beyond outfit anymore on its own, you either have to buy a complete skins pack or The Arkham Bundle (which also has Nightwing and Robin [Robin has his own skins!] and all of the other skins) However if you want a free skin, the Batman Inc. Batsuit is available for free.