| Northwood Plymouth Limited | Real estate | 2004 |
| Northwood Plymouth Waterfront Limited | Financial services | 2020 |
| Norton Avonmouth Limited | Real estate | 2015 |
| Norton Group Holdings Limited | Financial services | 2015 |
| Norton Stowmarket Limited | Real estate | 2022 |
| Nostromo Frontier Ltd | Manufacturing | 2025 |
| NOT2L8 Ltd. | Financial services | 2020 |
| Notchstores Ltd | Wholesale & retail | 2026 |
| Notion Architects Ltd | Professional & scientific | 2022 |
| Notontheforecourt Ltd | Wholesale & retail | 2015 |
| Notte Street Catering Ltd | Hospitality | 2020 |
| Notter Mill Country Park Limited | Hospitality | 2023 |
| Nous Vous Ltd. | Arts & recreation | 2015 |
| Nova Foods Limited | Hospitality | 1990 |
| Nova Outline Ltd | Construction | 2025 |
| Nova Solaris Limited | Financial services | 2021 |
| Novahomes Plymouth City Limited | Other services | 2015 |
| Novaworth Limited | Construction | 2018 |
| Novi Studios Limited | Health & social care | 2024 |
| Novus Flooring Limited | Construction | 2024 |
| Nowesm Limited | Professional & scientific | 2022 |
| Noys 3D Prints Ltd | Manufacturing | 2026 |
| NPN Systems Ltd | Construction | 2026 |
| Npsf Ltd | Manufacturing | 2023 |
| NR Creative Direction Limited | Information & communication | 2016 |
| NRG Transport Ltd | Transport & logistics | 2017 |
| NS Cleaning and Maintenance Ltd | Construction | 2020 |
| NS Parquet Ltd | Wholesale & retail | 2011 |
| NSA Pizza Limited | Hospitality | 2024 |
| NSV (Plymouth) Limited | Other services | 2013 |
| NT Group Enterprises Limited | Financial services | 2021 |
| NTC Kitchens & Bedrooms Limited | Construction | 2020 |
| NTL CAD Services Ltd | Professional & scientific | 2019 |
| NTL Global Ltd | Other services | 2018 |
| Ntmc Limited | Other services | 2014 |
| Ntradc Limited | Wholesale & retail | 2024 |
| NTS Business Services Limited | Transport & logistics | 2018 |
| NU Sign Marine Limited | Manufacturing | 2014 |
| Nucclear Limited | Professional & scientific | 2018 |
| Nudge Community Trading Limited | Other services | 2025 |
| Nudja AI Ltd | Information & communication | 2025 |
| NUMB3RS Business Services Ltd | Professional & scientific | 2015 |
| Numoplus Limited | Wholesale & retail | 1965 |
| Nurses Direct Home Care Limited | Health & social care | 2023 |
| Nurtivo Ltd | Professional & scientific | 2024 |
| Nurtura Connect Ltd | Administrative & support | 2026 |
| Nurtura Recruitment Ltd | Administrative & support | 2026 |
| Nurturing UK Limited | Health & social care | 2024 |
| Nutraceutic Ltd | Wholesale & retail | 2020 |
| Nuttalls (Plymouth) Limited | Real estate | 1953 |
| Nuzzl Ltd | Wholesale & retail | 2021 |
| NW Design & Build Limited | Construction | 2023 |
| NW Enterprises Ltd | Health & social care | 2013 |
| Nwse Limited | Wholesale & retail | 2025 |
| Nyon Limited | Real estate | 2025 |
| NZ Business Solutions Ltd | Professional & scientific | 2023 |
| Nzyme Catalyst Limited | Information & communication | 2023 |
| Nzyme Group Holdings Limited | Financial services | 2022 |
| Nzyme Trading Limited | Information & communication | 2019 |
| O & S Plumbing and Heating Ltd | Construction | 2014 |
| O and S Property Services Ltd | Real estate | 2019 |
| O'Lan Photography Ltd | Information & communication | 2025 |
| O.I Movers Limited | Transport & logistics | 2026 |
| Oacode Integrated Systems Ltd | Information & communication | 2026 |
| Oak City Limited | Extraterritorial | 2013 |
| Oakbridge Financial Limited | Financial services | 2026 |
| Oakdene Trading Ltd | Wholesale & retail | 2006 |
| Oakdens Limited | Wholesale & retail | 2003 |
| Oakeden Care Services Limited | Health & social care | 2024 |
| Oaklea Solutions Limited | Administrative & support | 2017 |
| Oakleigh Homes (Newquay) Limited | Construction | 2017 |
| Oakleigh Property Developments Limited | Construction | 2000 |
| Oakley Builders & Groundwork Contractors SW Ltd | Construction | 2017 |
| Oakley Holdings SW Ltd | Financial services | 2018 |
| Oakley Lettings Devon & Cornwall Ltd | Real estate | 2017 |
| Oakleys Accountants Limited | Professional & scientific | 2004 |
| Oakleys Carpentry Limited | Construction | 2025 |
| Oakleys Mini Coaches Ltd | Transport & logistics | 2023 |
| Oakmount (UK) Limited | Real estate | 2010 |
| Oakmount Automation Limited | Financial services | 2022 |
| Oakmount Control Systems Limited | Manufacturing | 2003 |
| Oakwell Performance Ltd | Health & social care | 2025 |
| Oasis Living SW Ltd | Construction | 2018 |
| Oasis Recoveryhousing CIC | Real estate | 2019 |
| OAT Motors Limited | Wholesale & retail | 2024 |
| Oates Transport Ltd | Transport & logistics | 2025 |
| Oatsy's Enterprises Ltd | Arts & recreation | 2024 |
| Oatway Design Ltd | Professional & scientific | 2015 |
| Obedair Ltd | Construction | 2015 |
| OBI Link Solutions Limited | Information & communication | 2025 |
| Obiwin Limited | Transport & logistics | 2025 |
| Objective Financial Planning Ltd | Financial services | 2022 |
| Objective Services Ltd | Administrative & support | 2024 |
| OC Blue Limited | Administrative & support | 2024 |
| OC Food Limited | Hospitality | 2021 |
| Occidens Limited | Health & social care | 2018 |
| Occupyearly Limited | Real estate | 1994 |
| OCD Cleaning Services South West Ltd | Administrative & support | 2021 |
| Ocean Adventures Ltd | Arts & recreation | 2017 |
| Ocean Barbers Ltd | Other services | 2023 |