| Rugbytots Limited | Arts & recreation | 2007 |
| Rumble Strip Ltd | Professional & scientific | 2002 |
| Russell Networks Limited | Information & communication | 2003 |
| Russo Enterprises Ltd | Wholesale & retail | 2016 |
| Ryan Builders Limited | Construction | 1997 |
| Ryan Leisure Limited | Arts & recreation | 1999 |
| Ryde Teaching Services Limited | Administrative & support | 2003 |
| Ryefield Delamare Limited | Professional & scientific | 2003 |
| Ryelands Developments Limited | Real estate | 2002 |
| S & R Plumbing and Heating Limited | Construction | 2007 |
| S B M Rail Limited | Construction | 2014 |
| S D Royce Consulting Limited | Professional & scientific | 2007 |
| S H Property Agents Limited | Real estate | 2001 |
| S J D Jewellery Ltd | Manufacturing | 2022 |
| S J Engineering Limited | Construction | 2002 |
| S K Regulatory Ltd | Information & communication | 2021 |
| S L C (Bourne) Limited | Hospitality | 1969 |
| S Mccracken & SON Ltd | Construction | 2003 |
| S&A (EC) Limited | Professional & scientific | 2019 |
| S. B. Electronic Systems Limited | Manufacturing | 1967 |
| S.C. Finance (Herts) Limited | Financial services | 2006 |
| S.E.Connor(Locksmiths)Limited | Wholesale & retail | 1972 |
| S.G. Electrical Services Limited | Construction | 1998 |
| S.P.B. Digital Imaging Limited | Professional & scientific | 2001 |
| S.R. Rawlings Limited | Construction | 2001 |
| S.R.D.S. Limited | Administrative & support | 2002 |
| Sacramento Street Limited | Professional & scientific | 1982 |
| Safe Air Ltd | Wholesale & retail | 2004 |
| Safe Medical Travel Ltd | Administrative & support | 2025 |
| Safecutters U.K. Ltd | Administrative & support | 2004 |
| Safestore Acquisition Limited | Professional & scientific | 2003 |
| Safestore Group Limited | Professional & scientific | 2003 |
| Safestore Holdings PLC | Professional & scientific | 2003 |
| Safestore Investments Limited | Financial services | 2006 |
| Safestore Properties Limited | Real estate | 1996 |
| Safetots Limited | Wholesale & retail | 2004 |
| SAI RAM Variety Grocers Ltd | Wholesale & retail | 2015 |
| Salon Beautec Limited | Other services | 2004 |
| Salsven Technology Limited | Information & communication | 2007 |
| Saltpress Limited | Real estate | 1985 |
| SAM Woodward Ltd. | Information & communication | 2000 |
| Samartha Limited | Other services | 2010 |
| Samson Electrical Services Limited | Energy | 2005 |
| Samuel Kane Limited | Arts & recreation | 2002 |
| Samuel Worboys Limited | Real estate | 1943 |
| Samvel Markosyan Consulting Ltd | Information & communication | 2021 |
| Sanctum Design & Build Ltd | Construction | 2025 |
| Sandhill Homes Limited | Construction | 1999 |
| Sandon Gate (Beaconside) Management Company Limited | Households | 2026 |
| Sandstar Wealth Limited | Administrative & support | 2019 |
| Sango Properties Ltd | Real estate | 2019 |
| Sargent & Bigwood Limited | Extraterritorial | 1963 |
| Sash Doctor Double Glazed Sash Box Windows Limited | Manufacturing | 2024 |
| Satlaw Limited | Professional & scientific | 2010 |
| Saxon Park (Warrington) Management Company Limited | Households | 2007 |
| Saxon Properties Limited | Administrative & support | 2014 |
| SB Drain Services Ltd | Water & waste | 2018 |
| SB Homes & Lettings Ltd | Real estate | 2025 |
| Scaff-Hire Services Ltd. | Construction | 1998 |
| Scantlebury Farm Services Limited | Agriculture & fishing | 2006 |
| Scarlet Creative Solutions Limited | Information & communication | 2005 |
| Scarlet Print Solutions Limited | Manufacturing | 2006 |
| Schat-Davit Company (Alnwick) Limited | Energy | 1985 |
| Scheems Limited | Other services | 1998 |
| Schottlander Limited | Professional & scientific | 1991 |
| Schottlander Medical Limited | Health & social care | 2010 |
| Scimitar Midco Limited | Extraterritorial | 2011 |
| Scimitar PFS 1 Limited | Extraterritorial | 2011 |
| Scimitar Topco Limited | Professional & scientific | 2011 |
| Sciom Limited | Professional & scientific | 2022 |
| Sciondene Limited | Wholesale & retail | 2004 |
| SCL Care Limited | Health & social care | 1999 |
| Scorpion Midco Limited | Extraterritorial | 2013 |
| Scorpion PFS 1 Limited | Extraterritorial | 2013 |
| Scott & Sons Limited | Administrative & support | 1990 |
| Scott Sampson Architects Ltd | Professional & scientific | 1997 |
| Scout Design & Communicate Ltd | Professional & scientific | 2002 |
| SCR Estates Limited | Real estate | 2003 |
| Screwface Forever Ltd | Wholesale & retail | 2019 |
| Sculptor Limited | Information & communication | 1980 |
| Seaberry Limited | Real estate | 2000 |
| Seaess Designs Limited | Manufacturing | 2002 |
| Seagold Mine Limited | Wholesale & retail | 2015 |
| Sealing & Hardware Solutions Limited | Wholesale & retail | 2001 |
| Search 4 Space Ltd | Real estate | 2000 |
| Sebastian Meakin Limited | Extraterritorial | 2005 |
| Secomak Limited | Manufacturing | 1930 |
| Seeleys Stores Limited | Real estate | 1964 |
| Seemus Ltd | Health & social care | 2004 |
| Selito Studio Ltd | Professional & scientific | 2021 |
| Sellarea Limited | Information & communication | 2004 |
| SEN Spa Group Ltd | Other services | 2025 |
| Senior PLC | Professional & scientific | 1933 |
| Senlodge Limited | Households | 1978 |
| Sensonics Limited | Manufacturing | 1997 |
| Sensors UK Limited | Manufacturing | 1999 |
| Sentaur Services Limited | Construction | 2017 |
| Serendipity Aneyn Limited | Wholesale & retail | 2025 |
| Serenity Financial Planning Ltd | Financial services | 2006 |
| Sermet Properties Ltd | Real estate | 2020 |