| RGK Property Management Limited | Real estate | 2021 |
| Richard Preston Consultancy Limited | Professional & scientific | 2021 |
| Right Track Logistics Limited | Professional & scientific | 2012 |
| Rise Fashion Ltd | Wholesale & retail | 2012 |
| Rise Pilates Limited | Arts & recreation | 2023 |
| River Tees Renewable Solutions Ltd | Construction | 2025 |
| Riverwood Properties Limited | Real estate | 1990 |
| RLS of Yarm Limited | Construction | 2013 |
| Robsons Garage Ltd | Wholesale & retail | 2025 |
| Rockfort Gulf Ltd | Real estate | 2023 |
| Roseberry Gifts Ltd | Wholesale & retail | 2021 |
| Roses's Roses Limited | Health & social care | 2022 |
| Roud Scents Ltd | Wholesale & retail | 2025 |
| RT100 Engineering Ltd | Wholesale & retail | 2022 |
| Rudby Investments Limited | Real estate | 2013 |
| Rudby LEA Services Ltd | Professional & scientific | 2025 |
| S & C Commissioning Ltd | Professional & scientific | 2019 |
| S Hodgman Construction Services Ltd | Construction | 2014 |
| S P S Signs Limited | Wholesale & retail | 2002 |
| S R Thornton Builders Limited | Construction | 2013 |
| S&G Watson (Teesside) Limited | Transport & logistics | 2020 |
| S&L Watson (Properties) Limited | Real estate | 2021 |
| Saetas Ltd | Professional & scientific | 2026 |
| Safeline Limited | Professional & scientific | 2005 |
| Sagan Properties North East Ltd | Real estate | 2022 |
| Saks Yarm Limited | Other services | 2011 |
| Salternergy Limited | Construction | 2016 |
| Sam’S Affordable Vans Ltd | Wholesale & retail | 2025 |
| SAN SEB Coffee Ltd | Hospitality | 2021 |
| Santo Survey Limited | Professional & scientific | 2025 |
| Santoro's Limited | Hospitality | 1999 |
| Sarah Elder Nutrition Ltd | Health & social care | 2021 |
| Sarah Hopper Neuropsychology Ltd | Health & social care | 2021 |
| Sarah Johnson Facialist Ltd | Other services | 2025 |
| Saravi Healthcare & Education Ltd | Professional & scientific | 2016 |
| School House Recruitment Ltd | Administrative & support | 2010 |
| SDI Yarm Ltd | Professional & scientific | 2020 |
| SED8 Solutions Ltd | Health & social care | 2023 |
| Sendsational Learning Ltd | Education | 2025 |
| Senni Consultancy Ltd | Professional & scientific | 2019 |
| SFP Facades Limited | Professional & scientific | 2017 |
| Shackleton Rodgers Ltd. | Professional & scientific | 2011 |
| Sharpe Medical Accounting Ltd | Professional & scientific | 2011 |
| Sheraton Parking Ltd. | Administrative & support | 2017 |
| Shil & Yush Ltd | Health & social care | 2016 |
| Shivram Consulting Ltd | Professional & scientific | 2026 |
| Shrav Medical Limited | Health & social care | 2025 |
| Simcox Services Ltd | Administrative & support | 2017 |
| Simon Boyle & Co Ltd | Real estate | 2006 |
| Simply Lean and Sigma Transformation Ltd | Professional & scientific | 2011 |
| Siya UK Properties Ltd | Real estate | 2022 |
| Sjap Solutions Limited | Professional & scientific | 2016 |
| Skandu Ltd | Health & social care | 2025 |
| Skills to Succeed Tutoring Ltd | Education | 2022 |
| Smallcow Limited | Information & communication | 2021 |
| Smart Developers Limited | Construction | 2014 |
| Smilecare Clinic Ltd | Health & social care | 2024 |
| Smkdiagnostics Ltd | Health & social care | 2023 |
| Solway Equine Vets Limited | Professional & scientific | 2021 |
| South Manor Management Company Limited | Real estate | 2013 |
| Southern Bay Leisure Limited | Hospitality | 2015 |
| Sparts Online Ltd | Wholesale & retail | 2025 |
| Spruced Ltd | Administrative & support | 2023 |
| SPS Properties N.E. Ltd. | Real estate | 2018 |
| SRP Projects Limited | Professional & scientific | 2010 |
| ST Martins Consultancy Ltd | Professional & scientific | 2023 |
| Stag Properties Investment Limited | Real estate | 2025 |
| Starlight Engineering Ltd | Professional & scientific | 2025 |
| Stephen Traut Consulting Ltd | Professional & scientific | 2025 |
| Sterling Small Ship Engineering Ltd | Real estate | 1993 |
| Steve Peckover Ltd | Information & communication | 2014 |
| Steven Hodgson Limited | Professional & scientific | 2025 |
| Stockton on Tees Crime Prevention Ltd | Administrative & support | 1997 |
| Stranks Consultants Limited | Information & communication | 2025 |
| Stranks Group Limited | Financial services | 2025 |
| Subtex Limited | Administrative & support | 2017 |
| Sunntics Limited | Professional & scientific | 2017 |
| Sunshine People C.I.C. | Information & communication | 2019 |
| Surgicalpharo Ltd | Health & social care | 2024 |
| Suzuki Techno Europe Ltd | Wholesale & retail | 1996 |
| Swales Motorsport Ltd | Arts & recreation | 2021 |
| Swan Hunter (Tyneside) Limited | Energy | 1995 |
| Swanson Cardiology Services Ltd | Health & social care | 2026 |
| Sworn Blade Engineering Ltd | Professional & scientific | 2024 |
| T Doocey Developments Limited | Real estate | 2024 |
| T MC Removals Ltd | Construction | 2025 |
| T&H Healthcare Ltd | Health & social care | 2025 |
| T.P.M. Services Limited | Construction | 2008 |
| Tailored Health Ltd | Health & social care | 2026 |
| Talk Cancer Teesside Limited | Professional & scientific | 2026 |
| Tanton Feeds Limited | Wholesale & retail | 2000 |
| Tapp Technologies Ltd | Information & communication | 2023 |
| Tarran Holdings Limited | Professional & scientific | 1987 |
| Tarran Properties Limited | Construction | 1988 |
| Taylor Electrical Contractors of Yarm Ltd | Construction | 2013 |
| Taylor Properties NE Ltd | Real estate | 2024 |
| TBM Gummies Ltd | Wholesale & retail | 2025 |
| TCH Developments Limited | Financial services | 2015 |
| Team Stokes Limited | Energy | 2010 |
| Technology Globe Ltd | Information & communication | 2020 |