| Newcastle Fencing & Sports Trust | Arts & recreation | 2013 |
| Newcastle Film Club Ltd | Information & communication | 2025 |
| Newcastle Financial Planning Ltd | Professional & scientific | 2022 |
| Newcastle Fireplace Centre Limited | Wholesale & retail | 1997 |
| Newcastle Fireplace Services and Manufacturing Limited | Manufacturing | 2013 |
| Newcastle Fitness Club Limited | Arts & recreation | 2026 |
| Newcastle Flight Simulators Ltd | Arts & recreation | 2019 |
| Newcastle Flooring Company Holdings Limited | Financial services | 2015 |
| Newcastle Flying School Limited | Arts & recreation | 2015 |
| Newcastle Foot Clinic Limited | Health & social care | 2005 |
| Newcastle Fringe Festival Ltd | Arts & recreation | 2023 |
| Newcastle Furniture Centre Ltd | Wholesale & retail | 2018 |
| Newcastle Furniture Company (Fulham) Limited | Wholesale & retail | 2010 |
| Newcastle Futsal Partnership Ltd | Arts & recreation | 2015 |
| Newcastle Garage Doors and Shutters Ltd | Administrative & support | 2017 |
| Newcastle Garage Services Ltd | Wholesale & retail | 2024 |
| Newcastle Garden Limited | Hospitality | 2025 |
| Newcastle GAS & Heating Ltd | Extraterritorial | 2018 |
| Newcastle GAS Ltd | Construction | 2014 |
| Newcastle GAS Services Ltd | Construction | 2010 |
| Newcastle GENR8 Kajima LLP | | 2022 |
| Newcastle Glob Ltd | Transport & logistics | 2024 |
| Newcastle Great Park (Estates) Limited | Real estate | 2007 |
| Newcastle Great Park Management Company Limited | Real estate | 2002 |
| Newcastle Groundworks Ltd | Construction | 2021 |
| Newcastle Gynaecology Clinic Ltd | Health & social care | 2020 |
| Newcastle Hair and Cosmetics Ltd | Wholesale & retail | 2024 |
| Newcastle Halal Superstore Limited | Wholesale & retail | 2018 |
| Newcastle Healthcare Property Company Limited | Administrative & support | 2014 |
| Newcastle Heating and Plumbing Ltd | Construction | 2017 |
| Newcastle Helix Developments LLP | | 2016 |
| Newcastle Helix LLP | | 2011 |
| Newcastle Helix Management LLP | | 2016 |
| Newcastle Home Buyers Limited | Real estate | 2017 |
| Newcastle Home Renovations Limited | Construction | 2023 |
| Newcastle Home Stagers Ltd | Professional & scientific | 2023 |
| Newcastle Homes Ltd | Real estate | 2017 |
| Newcastle Homes Plumbing and Heating Ltd | Construction | 2026 |
| Newcastle Hospitals Pharmaservices Limited | Health & social care | 2024 |
| Newcastle Hypnotherapy Ltd | Health & social care | 2020 |
| Newcastle Imaging Consultants Ltd | Health & social care | 2012 |
| Newcastle Independent Football Club Ltd | Arts & recreation | 2024 |
| Newcastle International Academy Limited | Education | 2017 |
| Newcastle International School Ltd | Education | 2019 |
| Newcastle ISC Limited | Professional & scientific | 2007 |
| Newcastle Jazz Cafe Ltd | Hospitality | 2016 |
| Newcastle K9 Day Care Limited | Other services | 2014 |
| Newcastle K9 Hydrotherapy Limited | Professional & scientific | 2016 |
| Newcastle K9 Nutrition Limited | Wholesale & retail | 2019 |
| Newcastle Kids Bikes CIC | Wholesale & retail | 2026 |
| Newcastle Legal Centre Limited | Information & communication | 2005 |
| Newcastle Lettings Co. Ltd | Real estate | 2011 |
| Newcastle Lock & Safe Company Ltd | Other services | 2011 |
| Newcastle Locksmiths & Safe Company Ltd | Other services | 2011 |
| Newcastle Locksmiths Ltd | Other services | 2011 |
| Newcastle Magpies Futsal Club Limited | Arts & recreation | 2025 |
| Newcastle Maintenance Limited | Construction | 2007 |
| Newcastle Mansion House Trading Company Limited | Hospitality | 2015 |
| Newcastle Marine Services Ltd. | Professional & scientific | 2015 |
| Newcastle Mead Ltd | Wholesale & retail | 2023 |
| Newcastle Medical Services Limited | Health & social care | 2003 |
| Newcastle Motor Company Ltd | Wholesale & retail | 2018 |
| Newcastle Muslim Burial Council Ltd | Other services | 2021 |
| Newcastle Muslim Centre | Other services | 2015 |
| Newcastle NE1 Limited | Other services | 2008 |
| Newcastle Neat Ltd | Hospitality | 2024 |
| Newcastle Nigerian Muslim Community Ltd | Health & social care | 2025 |
| Newcastle Optical Engineering Limited | Manufacturing | 2000 |
| Newcastle Padel Club Ltd | Arts & recreation | 2023 |
| Newcastle PAINTING&DECORATING24 Ltd | Manufacturing | 2025 |
| Newcastle Panto Limited | Arts & recreation | 2009 |
| Newcastle Park & FLY Limited | Transport & logistics | 1993 |
| Newcastle PIE and Mash Co Ltd | Hospitality | 2020 |
| Newcastle Pilates Limited | Extraterritorial | 2017 |
| Newcastle Plumbing & Heating Limited | Construction | 2008 |
| Newcastle Podiatry Ltd | Health & social care | 2021 |
| Newcastle Power Associates Ltd | Professional & scientific | 2015 |
| Newcastle Premier Health Limited | Health & social care | 2013 |
| Newcastle Preparatory School Trust Limited(The) | Education | 1960 |
| Newcastle Property & Estates Limited | Real estate | 2025 |
| Newcastle Property Group Ltd | Real estate | 2019 |
| Newcastle Property Investments Limited | Real estate | 2023 |
| Newcastle Property Solutions Limited | Real estate | 2026 |
| Newcastle Property Ventures Ltd | Real estate | 2018 |
| Newcastle Quran School Limited | Education | 2020 |
| Newcastle Real Estate Company Ltd | Real estate | 2020 |
| Newcastle Red Bulls KP Limited | Arts & recreation | 2014 |
| Newcastle Red Bulls Limited | Arts & recreation | 1999 |
| Newcastle Red Mezze Ltd | Hospitality | 2022 |
| Newcastle Removals Ltd | Transport & logistics | 2018 |
| Newcastle Renal Complement Therapeutics Consulting Limited | Administrative & support | 2020 |
| Newcastle Repair Centre Ltd | Wholesale & retail | 2023 |
| Newcastle Residential Holdings Ltd | Households | 2022 |
| Newcastle Roastery Ltd | Manufacturing | 2022 |
| Newcastle Roofers Ltd | Construction | 2025 |
| Newcastle Roofing & Building Ltd | Construction | 2026 |
| Newcastle Rugby Foundation | Arts & recreation | 2004 |
| Newcastle Running Clinic Limited | Health & social care | 2013 |
| Newcastle Salsa Club Ltd | Hospitality | 2026 |
| Newcastle School for Boys | Education | 1975 |