| Optivio Software Ltd | Information & communication | 2025 |
| Orchard Court (Bognor Regis) Freehold Limited | Real estate | 2023 |
| Orchard Garden Property Company Ltd | Households | 2019 |
| Orchard Lane (Hassocks) Residents Management Company Limited | Households | 2009 |
| Orchard Place Residents Limited | Households | 2016 |
| Ordwil Limited | Other services | 2019 |
| Organicmushroomsupplies.Com Limited | Hospitality | 2021 |
| Ormonde 1886 Ltd | Manufacturing | 2022 |
| Osborne Black & Co Ltd | Extraterritorial | 2026 |
| Osborne House Management Company Limited | Households | 1998 |
| Osca's Littlehampton Ltd | Hospitality | 2022 |
| OT Electrical Contractors Ltd | Construction | 2025 |
| Ourprice.Com Retail Limited | Wholesale & retail | 2021 |
| OUT of Bounds (Rustington) Ltd | Arts & recreation | 2014 |
| Outro Technology Limited | Administrative & support | 2024 |
| Overhill Group Limited | Real estate | 2019 |
| Oving Place Property Management Company Limited | Real estate | 1997 |
| Owens Consulting Engineers Ltd | Professional & scientific | 2021 |
| OWL Transport Ltd | Administrative & support | 2019 |
| P & H Electrical Solutions Ltd | Construction | 2014 |
| P a Windsor Building Contractors Limited | Construction | 2019 |
| P a Windsor Property Ltd | Real estate | 2016 |
| P and O Brickwork & Building Contractors Ltd | Construction | 2006 |
| P and O Construction Services Ltd | Construction | 2025 |
| P E Filtration Ltd | Manufacturing | 1994 |
| P1 Pistons Limited | Manufacturing | 2019 |
| P3D Print Ltd | Manufacturing | 2024 |
| PA Stansfield Limited | Professional & scientific | 2020 |
| Padel Installers UK Limited | Construction | 2025 |
| Padel Shark Ltd | Arts & recreation | 2025 |
| Paintball Fields Limited | Arts & recreation | 2012 |
| Pakhouse Ltd | Wholesale & retail | 2012 |
| Palamino Limited | Information & communication | 2017 |
| Pallant Catering Services Ltd | Hospitality | 2021 |
| Palm Cottage Limited | Real estate | 2018 |
| Panto Costumes Ltd | Administrative & support | 2024 |
| Parbrook Walk Billingshurst Residents Management Company Limited | Households | 2015 |
| Park Lodge Worthing Limited | Households | 2008 |
| Parker Premier Homes Limited | Construction | 2016 |
| Parsons OIL Heating Ltd | Construction | 2020 |
| Partnering Minds Ltd | Professional & scientific | 2026 |
| PAS Fork Lifts Ltd | Construction | 2017 |
| Pasun Limited | Health & social care | 2015 |
| PAT Barton Holdings Ltd | Financial services | 2017 |
| Patch Foods Ltd | Hospitality | 2026 |
| Paul Adams Windows Limited | Construction | 2010 |
| Paul Reddick Electrical Limited | Construction | 2014 |
| Paul Ryan (UK) Limited | Administrative & support | 2007 |
| Paws Pantry Ltd | Wholesale & retail | 2018 |
| Pawtry Ltd | Wholesale & retail | 2025 |
| Pbsa Consultancy Ltd | Administrative & support | 2025 |
| PC Doctor Ltd | Information & communication | 2025 |
| Peachey Software Solutions Ltd | Information & communication | 2018 |
| Peak Performance & Potential Ltd | Administrative & support | 2018 |
| Pearly Whites Clinic Limited | Health & social care | 2011 |
| Peck Property Services Limited | Real estate | 2014 |
| Pecketts Gate Owners Limited | Households | 2018 |
| Pedona Limited | Financial services | 2007 |
| Peel Leisure & Co. Ltd | Hospitality | 2002 |
| Peerless Marine Limited | Other services | 2019 |
| Pendleton Limited | Other services | 1989 |
| Penhallow Limited | Professional & scientific | 2015 |
| Pepita Investments Limited | Real estate | 2019 |
| Peppers Court Limited | Households | 1984 |
| Peregrines Court Management Company Limited | Households | 1984 |
| Perfectpose-Events Ltd | Professional & scientific | 2025 |
| Perpetual Business Management Ltd | Professional & scientific | 2022 |
| Personalised Pretties Galore Limited | Wholesale & retail | 2025 |
| Pest Stop Boys Limited | Administrative & support | 2019 |
| Pest ZAP Environmental Services Ltd Ltd | Wholesale & retail | 2026 |
| Pete's Plumbing and Heating Ltd | Construction | 2021 |
| Peter Hale Limited | Real estate | 2002 |
| Peter Slowe Limited | Administrative & support | 2019 |
| Petrocost Solution Limited | Transport & logistics | 2019 |
| Pets Parlour Ltd | Other services | 2018 |
| PH Pools Ltd | Construction | 2026 |
| Phillip Curtis Ltd | Health & social care | 2002 |
| Phoenix Cleaning Sussex Ltd | Administrative & support | 2025 |
| Phoenix Cyber Search Limited | Administrative & support | 2025 |
| Phoenix House Chinese Takeaway Ltd | Hospitality | 2025 |
| Phoenix Threads Limited | Wholesale & retail | 2024 |
| Phpm Properties Limited | Real estate | 2018 |
| Phys Properties Limited | Real estate | 2022 |
| Pier Road Coffee & Art Limited | Arts & recreation | 2017 |
| Pilot Developments Southern Ltd | Construction | 2010 |
| Pinkas Ltd | Information & communication | 2007 |
| Pippin Homes Limited | Real estate | 2018 |
| Pittham Dental Limited | Health & social care | 2007 |
| Pixel PCS Limited | Manufacturing | 2024 |
| Planet Ahau 144 Ltd | Manufacturing | 2024 |
| Pluck and Shine Ltd. | Wholesale & retail | 2013 |
| Plumes IT Ltd | Information & communication | 2025 |
| Pole Position Pistons Limited | Manufacturing | 2019 |
| Pompey Cripps Limited | Other services | 2002 |
| Poonamallee Productions Limited | Arts & recreation | 2008 |
| Porter and Bond Estate Agents Limited | Real estate | 2024 |
| Portfield Estate Company Limited | Real estate | 1971 |
| Poseidon Plumbing & Heating Solutions Ltd | Construction | 2026 |
| Potter and Mooch Limited | Manufacturing | 2018 |
| Potter's House Preschool Limited | Education | 2020 |