Use this if your S3 has already been updated to Android 4.3 Jelly Bean.
This guide covers everything you need to know about downloading and installing software for the Samsung Galaxy S3 (GT-i9300 and its variants). 1. Identify Your Specific Model download samsung s3 software
Official links can often be found on regional support pages like Samsung Support NZ or Samsung Support India . Samsung Smart Switch Use this if your S3 has already been updated to Android 4
Before downloading any software, you must know your exact model number. Installing firmware for the wrong variant can permanently "brick" your device. The international 3G version. GT-i9305: The international 4G/LTE version. download samsung s3 software