You can join an Inn of Court if you are studying a qualifying law degree, or studied on or have been accepted onto a law conversion course, or have been exempted from or have successfully completed the academic stage of training.

Depending on the pathway to qualification you are following, you will have a specific point at which you need to join an Inn of Court.  This is a requirement of the Bar Standards Board - more information on when to join an Inn can be found on their website.

Instructions for joining Inner Temple can be found here.