Arts and sports given a voice.
Ms Thomas is head of communications at the Sports Council Wales, while Ms Jones is head of marketing and sales at Chapter Arts Centre in Cardiff.
They will join nine other members of the board, of which more than half are women, in offering their expertise and advice to members of the institute, while working to help develop, expand and increase the profile of marketing in Wales.
Ms Thomas is responsible for the Sports Council's marketing, press, public affairs and research and leads a team of 11 staff.
Ms Jones has worked in arts marketing for over two decades across Europe. She is an experienced trainer and speaker. She is also a part-time lecturer in arts marketing at the Royal Welsh College of Music and Drama.
She said: "I've been a member of the Chartered Institute of Marketing for several years and I'm consistently impressed by the way it represents, not just its members, but the voice of marketers across Wales.
"For me it's about raising the status of marketers whatever sector you work in and the institute's focus on training and continuing professional development has played a huge part in this over recent years." "Arts marketers have to be as creative as the art forms we promote and most of us work within very tight budgets. I hope my insights and experience will be valuable in helping the Institute in Wales to continue to build opportunities over the years ahead.
Richard Houdmont, director for Wales of the Chartered Institute of Marketing, said: "I'm thrilled to welcome Sin and Carol as members of the Wales board. They each bring a wealth of experience in marketing..
"They will not only represent the arts and sports industries, but also help the institute in Wales to meet the needs of the wider leisure market and 'not-for-profit' sectors.
"Our board now includes representatives of the most important industries in Wales, ranging from tourism to manufacturing, and it is also representative of our membership of which women members are in the majority."
ON BOARD: Sin Thomas, left, heads marketing at the Sports Council and Carol Jones at Chapter Arts