| Cash For Clothes Aureza | Recycling centre | Unit 4, in between the houses, 270-268 Newport Rd | Mon–Fri 09:00–17:00 |
| Catertech Services Ltd | Equipment supplier | Unit D1, West Point Industrial Estate, Penarth Rd | Mon–Fri 08:30–17:00 |
| Cathays Picture Framing & Gallery | Picture framing shop | 177 Malefant St | Mon–Fri 09:30–17:00 |
| Cathedral Orthodontics | Orthodontist | 80 Cathedral Rd | Mon–Thu 08:30–17:30 |
| CBM Decorators & Property Maintenance | Painter and decorator | 96 Llandaff Rd | Mon–Sat 09:00–17:00 |
| CBOF Group | Office refurbishment service | Unit 1, Charnwood Park, Clos Marion | Mon–Fri 09:00–17:00 |
| CCR Secretariat | Psychiatrist | 136 Newport Rd | Mon 10:00–16:00 |
| CDP Embroidery | Screen printer | Unit A2, Lakeview Business Park, Lamby Way | Mon–Fri 09:00–14:30 |
| Centregreat Fabrication | Cladding contractor | Brindley Rd | Mon–Fri 07:00–17:00 |
| Chalkhouse Kitchens Ltd | Furniture maker | 3 Bessemer Close 9, 10 Bessemer Cl | Mon 09:00–16:30 |
| Chambers Estate Agents - Sales and Lettings Agent | Property Management | Estate agent | 35 Merthyr Rd | Mon–Fri 09:00–17:30 |
| CHAPS.pro | Furniture rental service | The Hayes | Mon 09:00–17:00 |
| Chicken.com Cardiff (Halal) | Fried chicken takeaway | 13 Castle St | Thu 11:00–03:00 |
| ChipsAway Cardiff Car Care Centre | Car body shop | Unit 20, Cardiff Business Park, Lambourne Cres | Mon–Fri 08:00–16:00 |
| Christchurch United Church | Church | Llanedeyrn Dr | Mon–Sat 05:00–22:00, 22:30–00:00 |
| Circumcision Clinic Cardiff | Surgeon | 98 Wentloog Rd | Mon 09:00–17:00 |
| City Prom | Dress shop | 820 Newport Rd | Tue–Wed 12:30–17:30 |
| Clarity Copiers South Wales | Office supplies shop | Magellan Court, Beignon Cl | Mon–Fri 09:00–17:00 |
| Clockwork Maintenance and Refurbishment | Property maintenance | 248a City Rd | Mon–Fri 08:00–16:30 |
| Clogau | Jewellery store | 29 St David's Dewi Sant | Mon–Fri 09:30–20:00 |
| Cluckbite | Fast food restaurant | 1 Cowbridge Rd W | Mon 11:30–23:00 |
| College Fields - Accomplish | Halfway house | 413 Western Ave | Daily Open 24 hours |
| Cooke & Arkwright | Commercial property estate agent | 7-8 Windsor Pl | Mon–Thu 09:00–17:30 |
| Cooked Illustrations | Design agency | Startup Stiwdio, Adam St | Mon–Tue 10:00–16:00 |
| Cooker Spare Parts | Appliance parts supplier | Richards Pl | Mon–Fri 09:00–17:00 |
| Cornerstone | Conference centre | Charles St | Mon–Sat 09:00–17:00 |
| Cornerstone Finance Group | Finance broker | Unit E, Cardiff Gate Business Park, Copse Walk | Mon–Fri 09:00–17:00 |
| Cosgrove Builders Ltd | General contractor | 8 Cae Gwyn Rd | Mon–Fri 09:00–17:00 |
| CP Mental Wellbeing | Psychotherapist | CP Mental Wellbeing, Regus House, Malthouse Ave | Mon 10:00–22:00 |
| CPRA Business Rates, Capital Allowances & Rent Review Surveyors Cardiff | Surveyor | 3rd Floor, Capital Tower, Greyfriars Rd | Mon–Fri 09:00–18:00 |