Simon Peter and Thomas (who was also called Didymus) were there together with Nathanael from Cana in Galilee, the two sons of Zebedee, and two more disciples.
When they got back, they went upstairs to the room where they were staying. Here’s a list of those who were there: Peter, John, James, and Andrew, Philip and Thomas, Bartholomew and Matthew, James the son of Alphaeus, Simon the Zealot, and Judas the son of James.