| Portland Community Partnership Ltd | Other services | 2017 |
| Portland Cottages Limited | Hospitality | 2010 |
| Portland Harbour Authority Limited | Transport & logistics | 1994 |
| Portland Homes and Garden Rooms Ltd | Construction | 2022 |
| Portland Isle Limited | Agriculture & fishing | 2012 |
| Portland Lobo Enterprises Ltd | Households | 2019 |
| Portland Magic Ltd | Wholesale & retail | 2019 |
| Portland Motor Repairs Limited | Wholesale & retail | 2014 |
| Portland Museum Trust | Arts & recreation | 2007 |
| Portland Patios Property Maintenance Ltd | Administrative & support | 2021 |
| Portland Performance Ltd | Wholesale & retail | 2026 |
| Portland Port Limited | Transport & logistics | 1996 |
| Portland Relaxation Rooms Limited | Other services | 2026 |
| Portland Seaweed Spa Ltd | Health & social care | 2025 |
| Portland Shellfish Limited | Wholesale & retail | 1997 |
| Portland Steel Ltd | Manufacturing | 2022 |
| Portland Stone Firms Limited | Mining & quarrying | 1994 |
| Portland Therapy Fitness Limited | Arts & recreation | 2024 |
| Portwave Building and Maintenance Ltd | Construction | 2024 |
| Prestige Communications (Swindon) Ltd | Information & communication | 2018 |
| Print Team (Dorset) Limited | Manufacturing | 2003 |
| Project Plasma Ltd | Manufacturing | 2026 |
| Proudmarsh Limited | Households | 1988 |
| Prycize Ltd | Wholesale & retail | 2018 |
| Pufc Land Co Limited | Real estate | 2019 |
| Punchbowl Inn Portland Limited | Hospitality | 2007 |
| Quickmix Driveways Limited | Construction | 2011 |
| Quiddles Cafe Ltd | Hospitality | 2025 |
| R Tuning Portland Ltd | Wholesale & retail | 2025 |
| Rawles Carpentry & Kitchens Ltd | Construction | 2024 |
| Ray's Fish & Chips Shop Limited | Hospitality | 2021 |
| Red Dandelion Ltd | Construction | 2023 |
| Reflexions Therapy Services Ltd | Health & social care | 2020 |
| Remains Property Limited | Real estate | 2021 |
| Renworx Ltd | Wholesale & retail | 2024 |
| Revenuenexus Ltd | Information & communication | 2014 |
| Revive Pressure Cleaning Limited | Construction | 2011 |
| Revive Wild Sauna Ltd | Other services | 2023 |
| RJ Driverhire Limited | Transport & logistics | 2010 |
| ROB Mcilroy Music Ltd | Arts & recreation | 2024 |
| Rochester Care Home Limited | Health & social care | 2013 |
| Rufus Castle Portland Limited | Real estate | 2016 |
| S Nathan Ltd | Wholesale & retail | 2024 |
| Sable Limited | Wholesale & retail | 2019 |
| Safety and Automation Systems Limited | Information & communication | 2015 |
| Saffire Software Ltd | Information & communication | 2024 |
| Sand Sculptures UK Limited | Arts & recreation | 2010 |
| Scyeline Ltd | Wholesale & retail | 2020 |
| Seasonseek Ltd | Extraterritorial | 2024 |
| Second Light Media Limited | Information & communication | 2012 |
| Serra Property Ltd | Real estate | 2021 |
| Shawline Asset Management Limited | Wholesale & retail | 2004 |
| Shielded Solutions Limited | Information & communication | 2024 |
| Shock Sailing Limited | Manufacturing | 2018 |
| Solace Reef Limited | Administrative & support | 2014 |
| Solesisters&Co Ltd | Wholesale & retail | 2025 |
| Sourced IT Limited | Information & communication | 2009 |
| South Coast Crane Hire Limited | Administrative & support | 2007 |
| South Coast Embroidery Ltd | Manufacturing | 2022 |
| South Coast Industries (Portland) Limited | Wholesale & retail | 1984 |
| South Coast Steam Limited | Manufacturing | 2003 |
| South Dorset Community Sports Trust Limited | Arts & recreation | 1999 |
| South West Consulting Ltd | Health & social care | 2022 |
| South West Serpents Limited | Agriculture & fishing | 2024 |
| Sprinklers Group Limited | Extraterritorial | 2023 |
| Sprinklers Training Academy Ltd | Education | 2021 |
| ST Peter's Park Retirement Village Limited | Health & social care | 2018 |
| Stonezilla Ltd | Manufacturing | 2020 |
| Street-Impact-Programmes Ltd | Education | 2025 |
| Stripey Finds Ltd | Wholesale & retail | 2014 |
| Suckthumb Mews Limited | Real estate | 2014 |
| Sunny Soul UP Ltd | Wholesale & retail | 2016 |
| Tangold Management Limited | Households | 1989 |
| THE Beauty Deck Portland Ltd | Other services | 2025 |
| THE Breakwater Hotel (Opco) Limited | Hospitality | 2017 |
| THE Breakwater Hotel Asset Limited | Real estate | 2017 |
| THE Chickerell Steam and Vintage Show Community Interest Company | Arts & recreation | 2009 |
| THE Chiswell Community Trust | Administrative & support | 2003 |
| THE Codfathers (Weston) Limited | Hospitality | 2013 |
| THE Cubbyhouse Limited | Health & social care | 2011 |
| THE Dementia Training Company Limited | Health & social care | 2011 |
| THE Dorset Crab Company Limited | Manufacturing | 2008 |
| THE Green Goat Dorset Ltd | Education | 2024 |
| THE Hangout Climbing Ltd | Arts & recreation | 2019 |
| THE Island Carriage Company Ltd | Wholesale & retail | 2021 |
| THE Pathfinder Spirit, Inc. | | 2021 |
| THE Portland Association CIC | Other services | 2024 |
| THE Portland Sculpture and Quarry Trust | Education | 1999 |
| THE Portland Social Club Limited | Hospitality | 2018 |
| THE Ranch Dorset CIC | Education | 2022 |
| THE Ranch Sanctuary Ltd | Agriculture & fishing | 2026 |
| THE Real Estate Bureau Limited | Real estate | 2008 |
| THE Ruffles Hotel and Training Academy Ltd | Education | 2023 |
| THE Salty Chipper Trading AS Salty Towers Ltd | Hospitality | 2023 |
| THE Sanctuary Crisis Intervention Hub CIC | Health & social care | 2023 |
| THE Vibrant Kitchen Co Limited | Hospitality | 2025 |
| Thevintagekoi Ltd | Wholesale & retail | 2025 |
| Thomas Dunlop Limited | Real estate | 2005 |
| Thomson & White Limited | Administrative & support | 2025 |
| Thornton Foot Health Ltd | Health & social care | 2023 |