If this an AT&T phone you can get the PUK code from your online account or by contacting customer service. You only have 10 attempts to enter in the PUK code. If you enter in the wrong code too many times you will need a new SIM card. This link has the steps to get the PUK code from your online account. http://www.wireless.att.com/answer-center/main.jsp?t=solutionTab&ft=searchTab&ps=solutionPanels&locale=en_US&_dyncharset=UTF-8&solutionId=33534&isSrch=Yes