I've searched around and see that it uses a "mini-SIM" card. I'm not sure if its different than a Nano or regular sized SIM - I'd say it's not. However, you might want to try and connect with Samsung and provide them with the Model S3 you are looking to use and want to clarify the type of SIM you need.Getting conflicting info in a google search. Can someone tell me what size sim the mini uses? TIA