His disciples - Those that he had made when in Judea. These were Peter, Andrew, Philip, and Nathanael. They were not yet called to be apostles, but they believed that he was the Messiah. The miracle performed here was doubtless to convince them more fully that he was the Christ.
Related Commentaries of John 2:2
John 2:2
2 And both Jesus was called, and his disciples, to the marriage.