Ring ended his top-flight club career with Cardiff RFC in 1996 after the first Heineken Cup Final against Stade Toulousain. He moved into coaching with West Hartlepool RFC, Cardiff RFC, Penzance and Caerphilly RFC.
Currently coaching with Welsh Premier Division side Cross Keys RFC, Ring will leave his post to rejoin Cardiff.
Lee Jarvis continues his full-time role as Skills Coach with the Cardiff Blues.
John Huw Williams, Chairman of Cardiff RFC said,
"I'm glad that Cardiff RFC have secured the services of Mark to be our Backs Coach.
"We have some extremely talented backs playing for us and I'm sure Mark will be able to bring the best out of them."