| CXS Tools | Abrasives supplier | 77 Titus Way | Mon 09:00–17:00 |
| Cygnet Hospital Colchester | Hospital | Boxted Rd | Daily Open 24 hours |
| D Knight Landscapes | Lawn care service | 1, Colne View, Cottages | Fri Open 24 hours |
| D'Lights Event Catering - TV and Film Catering | Caterer | Unit 3c, scripts farm | Mon–Tue 09:00–17:00 |
| Daizys Wardrobe | Boutique | Alresford Business Centre, Main Rd | Wed–Fri 10:30–15:00 |
| Dani’s Deli | Deli | Plough Rd | Mon–Tue 06:00–16:00 |
| Day & Knight Essex Wedding & Documentary Photographer | Photographer | 83 Nelson St | Daily Open 24 hours |
| Dazzle Dry Cleaners | Dry cleaner | Highwoods, Colchester CO4 9BB | Mon 09:00–18:00 |
| Dear Grace - Home Interior & Lifestyle | Gift shop | 77 Church Rd | Mon–Fri 09:30–16:30 |
| Dedham Health & Wellbeing with Amy Horne | Health consultant | Long Rd W | Mon–Tue 08:00–20:00 |
| Delovelicious Cakes & Co | Catering food and drink supplier | Rectory Rd | Mon–Tue 09:00–17:00 |
| Dent Devils East Essex | Car bodywork mechanic | 5 Spindle St | Mon–Fri 08:00–18:00 |
| Dent Devils Ltd | Vehicle dent removal service | Acorn Place, Severalls Business Park, Heckworth Cl | Mon–Fri 09:00–17:00 |
| Dental Implant Centre Colchester | Dental implants periodontist | 13A Nayland Rd | Mon–Tue 09:00–17:30 |
| Designs In Wood | Kitchen furniture shop | Plough Road Centre, Plough Rd | Mon–Sat 09:00–17:00 |
| Desjoyaux Pools | Swimming pool contractor | 3 Conder Way | Mon–Fri 09:00–17:00 |
| Detect 2 Computer, Mobile & Tablet Repair | Computer repair service | Woodfield End | Mon–Fri 09:00–17:30 |
| Dharmabelle Yoga and Wellbeing - Colchester | Yoga instructor | 12 Trinity St | Mon 09:00–21:00 |
| Dilan Kebab House | Kebab shop | 356A Mersea Rd | Mon–Tue 16:00–22:30 |
| Direct Seafoods Colchester | Seafood wholesaler | Crown Court, Clough Rd, Severalls Park Industrial Estate | Mon–Thu 08:00–15:30 |
| Direct Travel Insurance | Insurance company | Digital House, Threshelfords Business Park, Inworth Rd | Mon–Tue 09:00–17:00 |
| Distinctive Wholesale Ltd | Distribution service | Unit C, Caxton Court, Newcomen Way | Fri 09:00–17:30 |
| DJC Commercials Limited | Mechanic | THE COACH STATION, Harwich Rd | Mon–Fri 07:30–16:30 |
| DK SCHWEIZER UK Ltd | Vehicle upholsterer | Westside Centre, 14a London Rd | Mon–Fri 09:00–17:00 |
| Dolphin IT Support & Consulting Services LTD | Computer consultant | 88 Dale Cl | Mon–Fri 09:00–17:00 |
| Dress Code Nine | Tienda de artículos para bodas | Unit 21, Allshots Enterprises, Woodhouse Ln | Tue 10:00–20:00 |
| Dylan IT | Computer service | 211a Shrub End Rd | Mon–Fri 08:00–16:00 |
| Dynamic Fireworks | Fireworks shop | Unit 18, Peartree Rd | Mon–Fri 09:00–17:00 |
| Dynamic Insulation Ltd | Insulation contractor | Unit 2, Oakford Place, Tog Ln | Mon–Tue 08:00–18:00 |
| e-Hardware | Hardware shop | 1A, Tey Brook Centre, Brook Rd | Mon–Fri 09:00–17:00 |