| Santos Bolanos Investments Ltd | Financial services | 2023 |
| Santos Bolanos Ltd | Financial services | 2023 |
| Santos Bolanos Properties Ltd | Real estate | 2023 |
| Sapphire Promo Ltd | Professional & scientific | 2017 |
| Saqr AL Arab Ltd | Wholesale & retail | 2025 |
| Sarah & SON Painting &Decorating Limited | Construction | 2026 |
| Sarnia Foods Ltd | Hospitality | 2012 |
| Sarrail Limited | Construction | 2022 |
| Sasquatch Design Services Ltd | Professional & scientific | 2013 |
| Sates Limited | Wholesale & retail | 2009 |
| Satoshi Nakamoto Corporation Limited | Arts & recreation | 2021 |
| Sausage Rules Limited | Hospitality | 2020 |
| Savage B*Tch Ltd | Other services | 2024 |
| Sawden & Sons Limited | Construction | 2018 |
| Saxon Auto Transport Ltd | Transport & logistics | 2025 |
| SB (North East) Holdings Ltd | Financial services | 2024 |
| SB Brookdale Services Limited | Construction | 2023 |
| SB Consultancy 365 Ltd | Other services | 2018 |
| SB Lettings (NE) Ltd | Real estate | 2020 |
| SB North East Consultants Ltd | Professional & scientific | 2018 |
| SB Structures Ltd | Professional & scientific | 2022 |
| SB TRANSPORT365 Ltd | Transport & logistics | 2024 |
| SBM RTM Company Limited | Households | 2015 |
| SBW Trading Limited | Wholesale & retail | 2017 |
| SCA Recycling Limited | Professional & scientific | 1883 |
| Scaife Properties (NE) Limited | Real estate | 2024 |
| Scaling Heights Limited | Information & communication | 2026 |
| Scandic Holdings Ltd | Financial services | 2025 |
| Scandinavian Windows & Doors Ltd | Construction | 2019 |
| Scanlan Construction Limited | Construction | 2023 |
| Scanlan IB Limited | Financial services | 2023 |
| Scarr Holdings Ltd | Wholesale & retail | 2018 |
| Scarr Properties Limited | Real estate | 2020 |
| Scattered Pictures Ltd | Information & communication | 2011 |
| Scholfield Project Solutions Limited | Administrative & support | 2014 |
| Scholfield Property Solutions Ltd | Construction | 2019 |
| School Accounting & Finance Services Limited | Professional & scientific | 2006 |
| School Aprons Ltd | Manufacturing | 2018 |
| Schott Packaging Limited | Wholesale & retail | 2016 |
| Schott Removals Limited | Transport & logistics | 2005 |
| Schott Transport Limited | Transport & logistics | 2000 |
| Scob Ltd | Professional & scientific | 2016 |
| Sconset Durham Ltd | Real estate | 2020 |
| Scoop & Savoury Ltd | Hospitality | 2025 |
| Scorton Village Store Ltd | Wholesale & retail | 2021 |
| Scotch Corner Caravan Park Limited | Hospitality | 2013 |
| Scotch Corner Paintball Village Limited | Arts & recreation | 2006 |
| Scott Andrews Butchers Ltd | Wholesale & retail | 2023 |
| Scott's Access Training Ltd | Administrative & support | 2016 |
| Scott's Gym Limited | Arts & recreation | 2024 |
| Scoutek Ltd | Professional & scientific | 2009 |
| Screentech (North East) Ltd | Manufacturing | 2010 |
| Scriptosphere Limited | Information & communication | 2026 |
| Scrumandegg Limited | Hospitality | 2025 |
| SCT Commerce Ltd | Wholesale & retail | 2022 |
| SD Roadstone Ltd | Construction | 2017 |
| Sday Ltd | Arts & recreation | 2023 |
| SDB Hospitality Ltd | Hospitality | 2026 |
| Sea & Land Welding Limited | Construction | 2013 |
| Seagraves Pallets Limited | Manufacturing | 2019 |
| Seamless Vending Ltd | Hospitality | 2022 |
| Search Engine Guru Ltd | Information & communication | 2018 |
| Seatrench Commercial Limited | Other services | 2025 |
| Sebastopol Inns Limited | Hospitality | 2009 |
| Sebi Logistic Ltd | Transport & logistics | 2020 |
| Secret Garden (Darlington) Limited | Education | 2014 |
| Securabull Facilities Limited | Construction | 2025 |
| Secure Energy Limited | Professional & scientific | 2023 |
| Secure One Motors Limited | Wholesale & retail | 2025 |
| Securenet Electrical Ltd | Construction | 2024 |
| SEE Holdings Limited | Financial services | 2016 |
| SEE IT Solutions Limited | Information & communication | 2026 |
| Sekondbrain AI Labs Limited | Information & communication | 2025 |
| Select Electrical NE Ltd | Construction | 2021 |
| Selectiv Estate Agents Limited | Real estate | 2024 |
| Selgo Intelligent Solutions Ltd | Wholesale & retail | 2019 |
| Sell My Caravan Ltd | Wholesale & retail | 2021 |
| Sense of Style (UK) Limited | Wholesale & retail | 2019 |
| Sensory TOYS4U Retail Ltd | Wholesale & retail | 2023 |
| Senteca Limited | Extraterritorial | 2017 |
| Sentinel Homes Limited | Extraterritorial | 1992 |
| Sentiro (UK) Limited | Information & communication | 2007 |
| Serendipity Pre-School Ltd | Extraterritorial | 2018 |
| Serious Businesswomen Ltd | Administrative & support | 2012 |
| SET Engineering Solutions Limited | Professional & scientific | 2015 |
| SETUP4SUCCESS Ltd | Professional & scientific | 2024 |
| Seven Lucky Horses Ltd | Transport & logistics | 2026 |
| Seven Stars Holdings Ltd | Hospitality | 2024 |
| Seville Partners Ltd | Administrative & support | 2016 |
| SEW Happy to Help CIC | Health & social care | 2024 |
| Seymours Limited | Wholesale & retail | 1997 |
| SFA & G Properties Ltd | Real estate | 2025 |
| SFC Corporation Limited | Financial services | 2024 |
| SFC Estate Properties Limited | Real estate | 2024 |
| Sfedi Awards Ltd | Professional & scientific | 2011 |
| Sfedi Enterprises Ltd | Administrative & support | 2007 |
| Sfedi Ltd | Extraterritorial | 2014 |
| Sfedi Solutions Ltd | Professional & scientific | 2010 |
| SG Home Care Services Ltd | Public administration | 2024 |
| SGA Commodities Limited | Wholesale & retail | 2019 |