| O'Briens Range Cookers Limited | Administrative & support | 2008 |
| O-Ring-Plumbing Ltd | Wholesale & retail | 2020 |
| O-Ring-Sporting Ltd | Wholesale & retail | 2020 |
| Oahu Consulting Ltd | Administrative & support | 2023 |
| Oakley Machinery Ltd | Wholesale & retail | 2023 |
| Obal Ventures Ltd | Wholesale & retail | 2025 |
| Observer Lunch Ltd | Wholesale & retail | 2025 |
| Ocse Ltd | Professional & scientific | 2025 |
| Offshore Power Ltd | Construction | 2011 |
| Olly Davy Ltd | Professional & scientific | 2019 |
| ON SET Welfare Limited | Professional & scientific | 2018 |
| One Point Two (China) Limited | Professional & scientific | 1995 |
| Open Doors Gallery Ltd | Wholesale & retail | 2017 |
| Openstorytellers, Limited | Education | 2009 |
| Optimain Ltd | Professional & scientific | 2016 |
| Optimistic Trout Productions C.I.C. | Arts & recreation | 2010 |
| Optimum FX London Ltd | Professional & scientific | 2017 |
| Orchardleigh Castle East Limited | Real estate | 2019 |
| Orchardleigh Castle West Limited | Real estate | 2019 |
| Orchardleigh Equipment Limited | Professional & scientific | 2021 |
| Orchardleigh Estates Limited | Hospitality | 1998 |
| Orchardleigh Golf Limited | Arts & recreation | 2020 |
| Orchardleigh Helicopters Limited | Transport & logistics | 2020 |
| Orchardleigh Holdings Limited | Hospitality | 2024 |
| Orchardleigh Limited | Hospitality | 2010 |
| Orchardleigh Park Ltd | Hospitality | 2001 |
| Organic Digital Projects Limited | Information & communication | 2015 |
| Oruz Sales Closing Ltd | Wholesale & retail | 2026 |
| Osceola Capital Ltd | Financial services | 2024 |
| Ossia Investments | | 2022 |
| Other Side Productions Ltd | Professional & scientific | 2025 |
| OUR House Hair Ltd | Other services | 2021 |
| OUR Ikigai Ltd | Professional & scientific | 2025 |
| Owens Sausages and Hams Limited | Manufacturing | 2023 |
| Oxford Dairy Limited | Wholesale & retail | 2017 |
| Oxidant Limited | Extraterritorial | 2008 |
| P Cole Ltd | Wholesale & retail | 2004 |
| P James Brickwork Ltd | Construction | 2022 |
| P Rudge Limited | Professional & scientific | 2015 |
| P W Automotive Ltd | Transport & logistics | 2024 |
| P W Civils Ltd | Construction | 2014 |
| P&B Green Tech Ltd | Wholesale & retail | 2025 |
| P1 Interiors Ltd | Construction | 2016 |
| P2P Transport Limited | Transport & logistics | 2022 |
| Pack-It Self Storage Limited | Transport & logistics | 2018 |
| Paint Zero Limited | Manufacturing | 2023 |
| Pallet Suppliers Limited | Manufacturing | 1994 |
| Palm ST Pilates Ltd | Arts & recreation | 2025 |
| Palmer Rooms Limited | Hospitality | 2025 |
| Palmer Street Bottle Ltd | Hospitality | 2017 |
| Paperworks Virtual Assistance Limited | Professional & scientific | 2017 |
| Papilio Interiors Ltd | Construction | 2013 |
| Paravel Education Ltd | Education | 2024 |
| Parc Ponies Ltd | Administrative & support | 2022 |
| Parker and Corrin Limited | Construction | 2024 |
| Parkerinc Design Limited | Information & communication | 2003 |
| Parr Farming Limited | Manufacturing | 2012 |
| Part 2 Hair Salon Limited | Other services | 2006 |
| Party Bench Limited | Administrative & support | 2012 |
| Pastimeproperty Ltd | Real estate | 2024 |
| PAT Hinton Ltd | Information & communication | 2019 |
| Paul L Charlton SON & Daughter Ltd | Transport & logistics | 2023 |
| Paul L.Charlton Ltd | Transport & logistics | 2023 |
| Paul V Reynolds Ltd | Construction | 2013 |
| Paula Scott Ltd | Professional & scientific | 2021 |
| Paulina Folaron Consulting Ltd | Administrative & support | 2023 |
| PAV Build a Home Limited | Construction | 2026 |
| Paxtons Estate Agents (Lettings) Limited | Real estate | 2015 |
| Paxtons Estate Agents (Sales) Limited | Real estate | 2013 |
| PAY My Nanny Limited | Professional & scientific | 2012 |
| Payman.Co.Uk Ltd | Professional & scientific | 1999 |
| Payrun.Io Limited | Information & communication | 2017 |
| PCC Towing & Recovery Limited | Manufacturing | 2018 |
| Pdfee Ltd | Construction | 2012 |
| PDO Consulting Ltd | Professional & scientific | 2014 |
| Pearns Tree Services Ltd | Administrative & support | 2022 |
| Pearsonandbainton Limited | Hospitality | 2023 |
| Pebble Beach Property Ltd | Administrative & support | 2023 |
| Peloquin Properties Limited | Real estate | 2022 |
| Penn Equine Vets Limited | Professional & scientific | 2023 |
| Pentangle Limited | Information & communication | 1967 |
| Penwith Developments Limited | Construction | 2021 |
| Pepperbox Nursery Limited | Education | 2005 |
| Pepperell Investment Ltd | Real estate | 2021 |
| Pepperell Solutions Ltd | Transport & logistics | 2025 |
| Perianth Property Ltd | Real estate | 2023 |
| Permaframe Home Improvements Limited | Construction | 2022 |
| Permeable Stone Paving Ltd | Construction | 2025 |
| Perry 3D Ltd | Professional & scientific | 2025 |
| Perry Poppins Ltd | Administrative & support | 2022 |
| Perun Ltd | Professional & scientific | 2016 |
| Peter PAN Airways Limited | Professional & scientific | 1986 |
| Peter Schlesinger Healthcare Limited | Health & social care | 2015 |
| PFS Wiltshire Ltd | Administrative & support | 2019 |
| Phainon Ltd | Real estate | 2017 |
| Pheme Media Ltd | Information & communication | 2024 |
| Phil Date Contracts Ltd | Construction | 2020 |
| Phillips Land Management Ltd | Administrative & support | 2026 |
| Phoenix Electrical Contractors (South West) Ltd | Construction | 2012 |
| Phoenix HTB Ltd | Real estate | 2017 |