| ChipFlow | |
| Chits UK Ltd | Greater London |
| Chittak Ltd | |
| CHKS | |
| Chocolate Lime | |
| Choppity Ltd | |
| Chordata Ltd | |
| Chorus | |
| Chorus Global Ltd | Somerset |
| Chris Blunt | Devon |
| Chris Fickling Design | Nottinghamshire |
| Chris Lever SEO | |
| Chris Mackie | |
| Chris Marten | |
| Chris Young Design | |
| Christine Wilson | |
| Christopher Robinson | Cheshire |
| Chromacity Ltd | |
| Chromatin Bioscience Ltd | |
| ChromaTwist Ltd | |
| Chrome-Dome Design | Oxfordshire |
| Chrysalis Digital Ltd | |
| Chrysalis Training Ltd | Surrey |
| CHS Networks Ltd | Kent |
| Chucklefish Games | |
| Chunk Ideas Ltd | Glasgow |
| Chunky Frog Design Ltd | |
| Church International Ltd | Kent |
| ChurchDesk | |
| ChurchDesk Ltd | |
| Churchgate Computer Services | Suffolk |
| CiaoWeb | Swansea |
| CiberDirect | Greater Manchester |
| Cignon | Berkshire |
| Cimteq | Wrexham County Borough |
| Cinos Ltd | |
| CIP Merchant Capital | |
| Circad Design Ltd | Suffolk |
| Circadia Technologies Ltd | |
| Circle | Cardiff |
| Circle Cloud Ltd | |
| Circle Interactive | Bristol |
| Circle Software & Design Ltd | |
| Circle Square Ltd | Greater London |
| Circle.cloud | |
| Circlebox Creative Ltd | Greater Manchester |
| Circuit | |
| Circuit Mind Ltd | |
| Circulate Digital Ltd | |
| Circulor | |