| 1ES Group Ltd | Administrative & support | 2019 |
| 1ST Boston's MOT Station Limited | Wholesale & retail | 2022 |
| 26 ST Thomas Drive (Boston) Residents Company Limited | Households | 2007 |
| 300 Spartans Limited | Agriculture & fishing | 2019 |
| 3000GT / GTO Restoration Ltd | Wholesale & retail | 2021 |
| 3C&O Limited | Real estate | 2023 |
| 3D Safety Management Ltd | Professional & scientific | 2018 |
| 3DEM.CLINICAL Limited | Health & social care | 2018 |
| 3E International Limited | Professional & scientific | 2018 |
| 3H Dental Ltd | Health & social care | 2024 |
| 3HAPPYKIDZ Limited | Health & social care | 2014 |
| 4 ST Edmunds Terrace Management Company Ltd | Households | 2017 |
| 4G Agriculture Limited | Agriculture & fishing | 2012 |
| 4PAWSLOVER Ltd | Wholesale & retail | 2023 |
| 5 Star Nails & Beauty Ltd | Other services | 2025 |
| 70X7 Ltd | Administrative & support | 2013 |
| 786 24HED Ltd | Real estate | 2018 |
| A & D Properties (Lincolnshire) Limited | Real estate | 2024 |
| A & D Training Ltd | Education | 2002 |
| A & E Flowers Limited | Wholesale & retail | 2012 |
| A & S Properties (Lincolnshire) Limited | Real estate | 2024 |
| A B Boston Limited | Real estate | 2021 |
| A Coupland Labour Limited | Administrative & support | 2012 |
| A D Daskus Ltd | Transport & logistics | 2020 |
| A E L Biogas Limited | Energy | 1956 |
| A Jackson Builders Ltd | Construction | 2021 |
| A K Boston Ltd | Real estate | 2020 |
| A Marsh Brickwork Limited | Construction | 2024 |
| A Read Associates Ltd | Professional & scientific | 2014 |
| A Smith Ltd | Construction | 2018 |
| A Taste of Portugal Limited | Hospitality | 2021 |
| A Wiglusz Ltd | Transport & logistics | 2015 |
| A&A Help Services Ltd | Administrative & support | 2026 |
| A&Ar Transport Ltd | Transport & logistics | 2022 |
| A&D Real Estate Ltd | Real estate | 2025 |
| A&G Transport Services Ltd | Transport & logistics | 2026 |
| A&L&K Logistics Ltd | Transport & logistics | 2026 |
| A&S Complete Envelopes Limited | Construction | 2017 |
| A&V Trans Ltd | Transport & logistics | 2018 |
| A.B.K. Furnishings Limited | Wholesale & retail | 2010 |
| A.C.Jackson Builders Ltd | Construction | 2018 |
| A.Cheer & Sons,Limited | Wholesale & retail | 1938 |
| A.E. Lenton (Holdings) Limited | Financial services | 1961 |
| A.E. Lenton (Marketing) Limited | Agriculture & fishing | 1947 |
| A.E. Lenton Limited | Wholesale & retail | 1949 |
| A.G. Wilson (Promotions) Limited | Arts & recreation | 1967 |
| A.Gudvalis Ltd | Transport & logistics | 2025 |
| A.I.A. Shot Blasting Ltd | Manufacturing | 2019 |
| A.J. Grant Limited | Agriculture & fishing | 1973 |
| A.Pinchin Contracting Ltd | Agriculture & fishing | 2026 |
| A.R. Craven Farms Limited | Agriculture & fishing | 1995 |
| A1 Electrical Services Limited | Construction | 2018 |
| A26 Limited | Transport & logistics | 2025 |
| A3N Properties Limited | Real estate | 2025 |
| A4R Private Ltd | Transport & logistics | 2024 |
| AA Properties (Boston) Limited | Real estate | 2011 |
| Aade Motors Ltd | Wholesale & retail | 2026 |
| Aaelco Services Ltd | Construction | 2022 |
| Aamaz Traders Ltd | Wholesale & retail | 2024 |
| Aaron Stone Ltd. | Transport & logistics | 2011 |
| Aaron's General Builders Limited | Construction | 2015 |
| Aaryan Ltd | Wholesale & retail | 2019 |
| Aasi Services Limited | Health & social care | 2019 |
| AB Precision Valeting Ltd | Wholesale & retail | 2025 |
| AB Taxis Boston Ltd | Transport & logistics | 2025 |
| AB Trans 21 Ltd | Wholesale & retail | 2016 |
| Abbey Taxis (Boston) Ltd | Transport & logistics | 2011 |
| Abby Services Limited | Administrative & support | 2007 |
| ABC Boats (Boston) Limited | Manufacturing | 2018 |
| ABC Boats Ltd | Manufacturing | 2025 |
| ABC CNC and Fabrications Ltd | Manufacturing | 2024 |
| ABC Holdings (Boston) Ltd | Administrative & support | 2018 |
| ABD Transport Ltd | Transport & logistics | 2026 |
| Aberswift DE Leading Specialists Limited | Administrative & support | 2001 |
| Abey Houses Limited | Real estate | 2025 |
| ABH Maintenance Services Ltd | Manufacturing | 2022 |
| Ability Bathing Ltd | Construction | 2018 |
| ABS Engineering Ltd | Manufacturing | 2012 |
| ABS Property Rentals Ltd | Real estate | 2024 |
| ABS Systems Ltd | Information & communication | 2023 |
| Accessible Associates Limited | Administrative & support | 2020 |
| Accountability Contracts Ltd | Other services | 2024 |
| Accountants in Boston Limited | Professional & scientific | 2014 |
| Ace Events Limited | Arts & recreation | 2001 |
| ACH Motors Ltd | Extraterritorial | 2024 |
| Ackrill Close Management Company Limited | Households | 2010 |
| ACL Electrical and Building Services Limited | Construction | 2015 |
| ACM Engineering Solutions Ltd | Information & communication | 2013 |
| Acorn Taxis Boston Ltd | Transport & logistics | 2019 |
| Acres of Fencing Limited | Administrative & support | 2015 |
| AD Sports Coaching Ltd | Education | 2023 |
| ADA Cargo Limited | Transport & logistics | 2026 |
| Adam Keogh Golf Ltd | Arts & recreation | 2022 |
| Adaptus Consulting LLP | | 2013 |
| Adeadin Ltd | Administrative & support | 2020 |
| ADH Labour Providers Limited | Administrative & support | 2010 |
| Adhoc Accounts Limited | Professional & scientific | 2023 |
| Adrian Padley Motors Limited | Wholesale & retail | 2002 |
| Adrian Ratyis Ltd | Transport & logistics | 2024 |
| Adrijus Trans Ltd | Transport & logistics | 2015 |