I could not find a clearly listed dedicated Jain group based in Cardiff in the public Jain community listings I checked. The main UK Jain bodies are OneJAIN / Institute of Jainology and the Oshwal Association of the U.K., which coordinate Jain activity across the UK rather than only in Cardiff. ( onejainuk.org)

So, the practical answer is: there may be Jains in Cardiff, but I did not find a confirmed Cardiff-only Jain sangh or association in current public listings. ( onejainuk.org)

If you want, I can help you find the nearest Jain organisation serving South Wales or the wider UK Jain community.