Membership runs in calendar years and is available in several categories:

Fellow (FIBS)
Fellowship of the Institute may be awarded at the discretion of the Executive Committee following nominations from members (including existing Fellows). To qualify, a person must be "(operationally) outstanding in their area and/or have performed a long, honourable and highly regarded service to the IBS and/or to Broadcasting". Current Fellows of the Institute

Full Member (MIBS)
A Full Member shall be an individual who shows a depth and breadth of experience and responsibility in broadcast sound. They shall uphold the Code of Practice of the Institute in their professional dealings.
Applicants to this category shall ideally be nominated by two existing Full Members but appropriate references will also be considered.

Associate (AMIBS)
Open to all sound staff with current experience in broadcasting.

Student
Open to individuals who are undergoing full or part time education whose studies, activities or interests are closely associated with broadcasting. Student Members benefit from a specially discounted membership fee

Affiliate
This is a special category open to those who would not otherwise be eligible for membership. An Affiliate will typically be engaged at a senior level in manufacturing, research or training, or in some other activity closely connected with broadcasting.