| J D S Enterprises Ltd | Wholesale & retail | 2009 |
| J Delve Commercial Services Limited | Real estate | 2015 |
| J F a (SW) Ltd | Hospitality | 2024 |
| J Foods Exeter Ltd | Hospitality | 2025 |
| J G Security Limited | Administrative & support | 2014 |
| J Glenn Roofing Ltd | Construction | 2020 |
| J H Carnell Ltd | Construction | 2003 |
| J Hewings Stonework Specialists Ltd | Construction | 2021 |
| J J Carpentry & Building Ltd | Construction | 2013 |
| J J Phythian Limited | Information & communication | 2014 |
| J K M Building & Plastering Ltd | Construction | 2016 |
| J K Workshops Ltd | Hospitality | 2026 |
| J Knott Properties Limited | Real estate | 2013 |
| J L Design & Building Ltd | Construction | 2022 |
| J L Skinner Limited | Manufacturing | 2020 |
| J L Stone & Tiling Limited | Construction | 2015 |
| J M Property Developments Limited | Construction | 2007 |
| J M Spencer Consulting Limited | Professional & scientific | 2016 |
| J Oliver Property Limited | Real estate | 2026 |
| J P Bury Limited | Other services | 2003 |
| J P M Beds Ltd | Wholesale & retail | 2016 |
| J P Sibley & Sons Limited | Wholesale & retail | 2014 |
| J Poole Ltd | Manufacturing | 2024 |
| J Price Consulting Limited | Professional & scientific | 2013 |
| J R Banks Limited | Professional & scientific | 2011 |
| J R Carpets Limited | Wholesale & retail | 2004 |
| J R Engineering SW Ltd | Professional & scientific | 2025 |
| J Randell-Nash IFA Ltd | Financial services | 2022 |
| J Salles Ltd | Professional & scientific | 2024 |
| J Short & SON Limited | Administrative & support | 2003 |
| J Squared Retail Ltd | Wholesale & retail | 2025 |
| J T a (SW) Ltd | Agriculture & fishing | 2019 |
| J T Wealth Management Limited | Financial services | 2012 |
| J Tucker Properties Ltd | Real estate | 2022 |
| J W Stunts Ltd | Arts & recreation | 2025 |
| J Webber Holdings Ltd | Financial services | 2020 |
| J Wilson Electrical Limited | Construction | 2002 |
| J&B Light Properties Limited | Real estate | 1996 |
| J&B Residence Ltd | Real estate | 2021 |
| J&B Stays Ltd | Real estate | 2021 |
| J&C Construction (SW) Ltd | Manufacturing | 2025 |
| J&D Jones Limited | Hospitality | 2020 |
| J. C. P. Hawken Limited | Agriculture & fishing | 2006 |
| J. Chew Plumbing and Heating Limited | Construction | 2022 |
| J. Wippell & Company Limited | Manufacturing | 1902 |
| J.A.B. Security Ltd | Administrative & support | 2019 |
| J.A.S Building & Maintenance Ltd | Construction | 2023 |
| J.Elworthy Electrical Contractors Ltd | Construction | 2019 |
| J.F. Pipelines Limited | Transport & logistics | 2017 |
| J.N. Building Limited | Construction | 1988 |
| J.T. Auto's (SW) Ltd | Wholesale & retail | 2024 |
| J9OBR Limited | Administrative & support | 2024 |
| JA & TA Property Management Limited | Real estate | 2017 |
| JA Morton Consulting Ltd | Information & communication | 2019 |
| JAB Communications Ltd | Information & communication | 2023 |
| JAC Mechanical Design Engineering Ltd | Professional & scientific | 2021 |
| Jacardy Limited | Extraterritorial | 2015 |
| Jack Nicholas Dean Ltd | Arts & recreation | 2020 |
| Jack Simpson House Limited | Health & social care | 2017 |
| Jackpot Lane Ltd | Arts & recreation | 2026 |
| Jacob and Rosee Limited | Information & communication | 2013 |
| Jade Electronics Solutions Ltd | Manufacturing | 2022 |
| Jade Family Holding Company Ltd | Financial services | 2024 |
| Jade Horizons Ltd | Real estate | 2023 |
| Jaffar+Green Ltd | Professional & scientific | 2025 |
| JAH Development and Sound Ltd | Information & communication | 2017 |
| Jake 'N' JOE Trading Co. Limited | Wholesale & retail | 2018 |
| Jake Detergents Ltd | Manufacturing | 2023 |
| Jakub Sohe Art Ltd | Arts & recreation | 2025 |
| Jakyl Ltd | Information & communication | 2010 |
| Jalexconsulting Ltd | Health & social care | 2025 |
| JAM III Investments Limited | Construction | 2003 |
| JAM Motion Ltd | Information & communication | 2025 |
| James Beddall Ltd | Professional & scientific | 2023 |
| James Best Mortgages Ltd | Financial services | 2020 |
| James Bowden and SON Limited | Wholesale & retail | 2025 |
| James Consulting Services Limited | Professional & scientific | 2021 |
| James D Baird (Home Farm) Limited | Agriculture & fishing | 2007 |
| James O'Donnell Limited | Real estate | 2016 |
| James Patraiko Consulting Limited | Professional & scientific | 2023 |
| James Rayner Consulting Limited | Professional & scientific | 2018 |
| James Riggall Fine Joinery Ltd | Manufacturing | 2014 |
| James Van DER Steen Projects Ltd | Construction | 2021 |
| James Webber Recruitment Limited | Administrative & support | 1999 |
| Jameson & Sons Limited | Wholesale & retail | 2020 |
| Jameson Homes Limited | Construction | 2007 |
| Jamie Trant Limited | Arts & recreation | 2018 |
| Jamie’S Fencing & Landscaping Ltd | Administrative & support | 2025 |
| Jammy Brambles Ltd | Manufacturing | 2021 |
| Jamu Wild Ltd | Manufacturing | 2021 |
| JAN Stewer (Exeter) Ltd | Real estate | 2025 |
| Jane Evans Taxation Limited | Professional & scientific | 2010 |
| Janner Group Limited | Financial services | 2022 |
| Janus Group Limited | Administrative & support | 2025 |
| JAR Bakeries Holdings Ltd | Real estate | 2025 |
| Jarrett-Kerr Consulting Limited | Professional & scientific | 2002 |
| JAS Cars Limited | Transport & logistics | 2002 |
| Jasmin & Seresha Cafe Ltd | Hospitality | 2023 |
| Jasmins Cafe Ltd | Hospitality | 2022 |
| Jason Turner Building Contractor Limited | Construction | 2005 |