Is a micro-SIM the same thing as a micro-SD card?

No, a micro-SD card is a different product serving a different purpose. SD cards can’t do what SIM cards do, which is identify you to the network. The purpose of SD cards is tostore information, an SD card can hold gigabytes of multi-media files (pictures, music, videos, etc).

The micro-SIM’s primary function is to identify you to the carrier, and to run micro-applications to ensure you have the best experience of your carrier’s services.

 

See also :

How is a micro-SIM different from the SIM I have in my mobile phone now?