| Blanchard Wells Ltd | Civil engineering | The Meadows, Forester Rd | Mon–Thu 08:30–17:30 |
| Blue Bubble Lettings | Apartment letting agency | Blue Bubble Letting Limited, Enterprise House, Ocean Way | Mon 10:00–18:00 |
| Blue Funnel Cruises | Sightseeing tour agency | Office only, Ferry House, Ocean Way | Mon 09:30–12:30 |
| Blue Piranha Branded Clothing | Work clothes shop | Cedars nursery | Mon–Fri 09:00–17:00 |
| Bluebell Veterinary Surgery | Veterinarian | 7 Manor Cres | Mon–Fri 09:00–19:00 |
| Board on the Waterside | Hobby shop | Board On the Waterside 1&2, The Exchange, Beaulieu Rd | Mon–Fri 12:00–21:00 |
| BodyWorx Health Clinic | Chiropractor | Medino House | Mon 08:30–18:00 |
| Bold Boundaries Transport Ltd | Removals company | Flat B, 87 Alma Rd | Daily Open 24 hours |
| Boss Chix Lechon House UK | Grill | 158A Foundry Ln | Daily Open 24 hours |
| Botley Commercials Ltd | Truck repair shop | Bottings Industrial Estate, Hillsons Rd | Mon–Fri 08:00–17:00 |
| Botley Fencing | Fence contractor | 18 Sengana Cl | Mon–Sat 07:30–17:00 |
| Botley Flour Milling Company Ltd | Pet food and animal feeds | Botley Mills | Mon–Sat 08:30–17:00 |
| Botox and Skin Clinic | Pixel perfect clinic | Medical spa | Admiral suite, Royal mail house, Terminus Terrace | Mon–Wed 10:00–18:00 |
| Boxed Bridal | Specialist Wedding Dress Cleaners | Nationwide Service | Dry cleaner | Opposite Pressing Needs, Talisman Business Centre, 2, Duncan Rd | Tue 08:30–16:00 |
| BPMS Document Scanning & Digital Document Solutions | Business management consultant | White Building Studios, 1-4 Cumberland Pl | Daily 08:00–18:00 |
| Brand Your Team UK | Promotional products supplier | Neptune House, Merlin Quay, Hazel Rd | Thu 09:00–04:30 |
| Breaktime Coffee and Vending | Vending machine supplier | 11a W End Rd | Mon–Fri 08:00–18:00 |
| Breeze Volkswagen Van Centre Southampton | Volkswagen dealer | 331 Salisbury Rd | Sat 09:00–17:00 |
| Britannia Chauffeurs | Limousine service | 3 Marsh Ln, City Commerce Centre | Thu 08:00–22:00 |
| British Heart Foundation | Charity shop | 221 Portswood Rd | Mon–Sat 09:30–17:00 |
| Budget Car Hire - Southampton International Airport | Car rental company | Spitfire Loop | Mon–Fri 07:30–20:00 |
| Buds House UK | Smoke shop | 023 W End Rd | Daily Open 24 hours |
| Burga | Hamburger restaurant | 170 Portswood Rd | Mon–Thu 12:00–00:00 |
| Bursledon Community Centre | Community centre | Portsmouth Rd | Fri 07:00–14:00 |
| Business Accounting & Tax Ltd | Tax preparation service | 73 Holly Hill | Daily 09:00–23:30 |
| Butcher's Block | Butchers | 461 Fair Oak Rd | Tue–Fri 08:30–16:00 |
| Buttons & Bows Professional Alteration Service | Clothing alteration service | Unit 4, Northam Business Centre, Princes St | Mon–Tue 10:00–17:00 |
| BVM Ltd | Computer hardware manufacturer | Waltham Business Park, Lakeside House, Brickyard Rd | Mon 08:30–17:00 |
| BWT Southern Ltd | Waterproofing service | White Hart Stables, Bank St | Fri 08:00–17:30 |
| By Lauren Kimberly | Permanent make-up clinic | Portsmouth Rd, Lowford Hill | Wed 10:00–18:00 |