| ADD Lemonade Limited | Professional & scientific | 2020 |
| Add-Venture Advisory Ltd. | Extraterritorial | 2019 |
| Addictions Treatment Limited | Health & social care | 2018 |
| Addpad Limited | Real estate | 2022 |
| Adebak Ltd | Information & communication | 2021 |
| Adedan Services Limited | Wholesale & retail | 2024 |
| Adelec Ltd | Construction | 2016 |
| Adelodun Worldwide Services Ltd | Wholesale & retail | 2025 |
| Adept BS Limited | Professional & scientific | 2015 |
| Adept Electrical South Ltd | Construction | 2017 |
| Adept Solutions Recruitment Limited | Administrative & support | 2019 |
| ADG Building & Property Maintenance Ltd | Construction | 2023 |
| Adgenda Media International Services Ltd | Professional & scientific | 2025 |
| Adhitch Group Ltd | Financial services | 2026 |
| Adido Hold Limited | Financial services | 2020 |
| Adido Limited | Information & communication | 2003 |
| Adido Property Limited | Administrative & support | 2021 |
| ADK Capital Investments Ltd | Professional & scientific | 2025 |
| ADL Properties and Lettings Limited | Hospitality | 2026 |
| ADL Utilities Limited | Information & communication | 2016 |
| ADM Foods Ltd | Wholesale & retail | 2023 |
| Administaff Limited | Administrative & support | 2023 |
| Admiral's Point Management Company Limited | Households | 2006 |
| Admirals Court RTM Company Limited | Households | 2019 |
| Adonai Care Services Ltd | Administrative & support | 2017 |
| Adonai Elderly Care Ltd | Health & social care | 2024 |
| Adorned Investments Limited | Real estate | 2018 |
| Adrian Taxi Ltd | Transport & logistics | 2023 |
| Adrian Wilkes Limited | Construction | 1972 |
| Adriartim Limited | Construction | 2018 |
| Adric Watson Cinematographer Limited | Professional & scientific | 2023 |
| Adrienn Rozner Productions Ltd | Information & communication | 2025 |
| Adsm Properties Ltd | Real estate | 2020 |
| Advanced Biomechanics Consultancy Limited | Health & social care | 2017 |
| Advancing Homes Limited | Construction | 2016 |
| Advantage BIO Sciences Limited | Health & social care | 2018 |
| Advantage Group Hire Ltd | Wholesale & retail | 2017 |
| Adverse Camber Productions | Arts & recreation | 2009 |
| ADZ Limited | Information & communication | 1994 |
| AEA Products Ltd | Construction | 2024 |
| Aegis Cloud Limited | Real estate | 2011 |
| Aejb Trading Ltd | Extraterritorial | 2011 |
| Aemilius Limited | Real estate | 2025 |
| Aera Films Ltd | Information & communication | 2026 |
| Aerem Group Limited | Energy | 2022 |
| Aerial Yoga Bournemouth Ltd | Health & social care | 2015 |
| Aero & Space Analytics Ltd | Professional & scientific | 2015 |
| Aero Aviation Services Ltd | Transport & logistics | 2024 |
| Aeroflex Engineering Group Limited | Financial services | 2022 |
| Aeroflex Hose and Engineering Limited | Manufacturing | 1980 |
| Aerospace Expert Ltd | Professional & scientific | 2018 |
| Aesthetic & Smile Limited | Health & social care | 2020 |
| Aesthetic Beauty Park Ltd | Other services | 2022 |
| Aesthetics Rooms Dorset Ltd | Other services | 2026 |
| Aesthetics With Charlotte Ltd | Other services | 2025 |
| Aetheon Operations Ltd | Professional & scientific | 2025 |
| AEY Property and Investments Limited | Real estate | 2023 |
| AF Print Limited | Manufacturing | 2024 |
| AF18 Limited | Wholesale & retail | 2025 |
| AFC Bournemouth Community Sports Trust | Arts & recreation | 2007 |
| AFC Bournemouth Limited | Arts & recreation | 2008 |
| AFC Bournemouth Women Limited | Arts & recreation | 2025 |
| AFC Construction Limited | Construction | 2022 |
| AFD Property Group Ltd | Real estate | 2023 |
| Affa Homecare Ltd | Health & social care | 2025 |
| Affable Alternative Provision Ltd | Education | 2025 |
| Affanita Designs Ltd | Arts & recreation | 2018 |
| Affinity Architects Limited | Professional & scientific | 2014 |
| Affinity Records UK Ltd | Information & communication | 2019 |
| Affirm Health Limited | Health & social care | 2014 |
| Affordable Estate Agents Limited | Real estate | 2021 |
| Affordable Homes in the Sun Ltd. | Real estate | 2009 |
| Affordable Housing & Healthcare Investment Management Ltd | Real estate | 2017 |
| Affordable Housing and Healthcare Group Limited | Financial services | 2016 |
| Affordable Housing and Healthcare Group Secured Lending Limited | Financial services | 2015 |
| Affordable Housing and Healthcare Secured Lending LLP | | 2019 |
| Affordable Housing Communities Limited | Households | 2015 |
| Affordable Infrastructure UK Ltd | Financial services | 2020 |
| Affordable Luxury Ltd | Wholesale & retail | 2017 |
| Affordable Welding Repairs Ltd | Manufacturing | 2020 |
| Affordalife Ltd | Hospitality | 2025 |
| Afiyame Group Limited | Administrative & support | 2026 |
| Afonso Properties Limited | Real estate | 2025 |
| Afreen & Mataaf Ltd | Wholesale & retail | 2025 |
| Africa to Bournemouth CIC | Hospitality | 2025 |
| Afro*Disiac Live Radio CIC | Information & communication | 2012 |
| Afronaij UK Limited | Arts & recreation | 2025 |
| Afterglow Bournemouth Ltd | Other services | 2023 |
| Afternoon Sleeping Ltd | Information & communication | 2024 |
| AG Appdeploy Consultancy Limited | Information & communication | 2018 |
| AG Bridgen Limited | Real estate | 2022 |
| AG Car Zone Ltd | Wholesale & retail | 2025 |
| AG Chariots Ltd | Wholesale & retail | 2023 |
| AG Management Ltd | Arts & recreation | 2023 |
| AG Mpower Recruits Ltd | Administrative & support | 2024 |
| AG Property & Estates Limited | Construction | 2023 |
| AGA Real Estate Ltd | Real estate | 2019 |
| AGA Recruitment Solutions Limited | Administrative & support | 2012 |
| Agamemnon Engineering Ltd | Professional & scientific | 2010 |
| Agape Duck Intelligence Limited | Professional & scientific | 2025 |