| Scott & Wilkinson (Lancaster) Limited | Professional & scientific | 2018 |
| Scott Newton Limited | Administrative & support | 2015 |
| Scrap-Craft Studio C.I.C. | Wholesale & retail | 2025 |
| Scribe Northern Limited | Construction | 2007 |
| SDK Cleaners Ltd | Administrative & support | 2025 |
| Sea Fish Directory Limited | Other services | 2007 |
| Sea-Porters Ltd | Professional & scientific | 2021 |
| Seafront Stays Limited | Hospitality | 2024 |
| Sean Fagan-Wade Ltd | Transport & logistics | 2025 |
| Searchquest Europe Ltd | Information & communication | 2009 |
| Seasound Restaurant Ltd | Hospitality | 2021 |
| Second Life Device Limited | Wholesale & retail | 2020 |
| Securefence Ltd | Construction | 2019 |
| Security Window Shutters Limited | Manufacturing | 1987 |
| Sedojac Property Services Ltd | Construction | 2022 |
| Seeds for Change Lancaster Co-Operative Ltd | Education | 2001 |
| Seiton Ltd | Professional & scientific | 2018 |
| Selwyn Connect Ltd | Administrative & support | 2026 |
| Semi Threado Limited | Manufacturing | 2013 |
| SEN Adhd Services Limited | Health & social care | 2022 |
| Seneca National Limited | Professional & scientific | 2023 |
| SEO Lease Ltd | Information & communication | 2015 |
| Servizon Ltd | Administrative & support | 2023 |
| SET NW Holdings Limited | Financial services | 2023 |
| SET Sandblasting Limited | Administrative & support | 2023 |
| Settle Properties Ltd | Real estate | 2025 |
| Settled Software Limited | Information & communication | 2025 |
| SFP Enterprises Limited | Real estate | 2012 |
| SGK Strategies Ltd | Professional & scientific | 2025 |
| SH Construction (NW) Limited | Construction | 2024 |
| SH Senior Care Ltd | Health & social care | 2020 |
| Shackleton's of Bare Ltd | Hospitality | 2020 |
| Shacut NW Ltd | Other services | 2024 |
| Shadowdog Limited | Manufacturing | 2016 |
| Shane Jerman Consulting Ltd | Administrative & support | 2023 |
| Shard Riverside Lodge Park Limited | Hospitality | 2022 |
| Sharp Electrics Ltd | Construction | 2024 |
| Sherliker Biggs Limited | Professional & scientific | 2025 |
| Shining Star Productions Limited | Arts & recreation | 2024 |
| Shkh Limited | Administrative & support | 2024 |
| SHOP247 Ltd | Information & communication | 2020 |
| Shopex Ltd | Wholesale & retail | 2023 |
| Shore Thing Property Limited | Real estate | 2022 |
| Shorefields Supplies Limited | Wholesale & retail | 2021 |
| Shoreline Designs Ltd | Arts & recreation | 2022 |
| Shree SAI Kripa Ltd | Real estate | 2020 |
| Shutter Click Sion Ltd | Professional & scientific | 2026 |
| Sign Access Islands Ltd | Health & social care | 2024 |
| Sign OUT Loud Ltd | Education | 2020 |
| Silent COG Limited | Real estate | 2018 |
| Silent D Capital Ltd | Financial services | 2023 |
| Silent D Entertainment Ltd | Arts & recreation | 2017 |
| Silent D International Ltd | Information & communication | 2016 |
| Silent D Ltd | Information & communication | 2016 |
| Silent D Pictures Ltd | Information & communication | 2013 |
| Silent D Properties Ltd | Real estate | 2016 |
| Silent D Studios Ltd | Information & communication | 2015 |
| Siler Hrdge Trade Ltd | Wholesale & retail | 2025 |
| Silk Mill Garage Limited | Wholesale & retail | 2002 |
| Silva Retail Limited | Wholesale & retail | 2024 |
| Silver Tree Jewellery Co. Ltd. | Wholesale & retail | 2011 |
| Silverwood Inc. Ltd | Financial services | 2025 |
| Silverwood Property & Lettings Ltd | Real estate | 2024 |
| SIM Communications Ltd | Wholesale & retail | 2018 |
| Simon Fletcher Limited | Wholesale & retail | 2005 |
| Simpatico Roleplay Agency Ltd | Other services | 2013 |
| Simply Ecology Limited | Professional & scientific | 2011 |
| Simply Precast Accessories Limited | Construction | 2010 |
| Sinan AGA Ltd | Hospitality | 2025 |
| Singh & Donaldson Limited | Wholesale & retail | 2001 |
| Singhandkaur Stores Ltd | Wholesale & retail | 2025 |
| Sinkfall Farm Limited | Extraterritorial | 2004 |
| Sinkfall Waste Management Limited | Professional & scientific | 2019 |
| SIP Tea Co Ltd | Manufacturing | 2024 |
| Sirvent IS Consulting Ltd | Professional & scientific | 2011 |
| Sisasu Ltd | Real estate | 2014 |
| Sitil Ltd | Professional & scientific | 2011 |
| SIXTEEN62 Limited | Professional & scientific | 2018 |
| Sixty Trinity Limited | Real estate | 2019 |
| SJ Pubs and Bars Limited | Hospitality | 2019 |
| SJH Food Solutions Ltd | Wholesale & retail | 2024 |
| SJM Property & Services Ltd | Real estate | 2025 |
| SJT Academic Services Ltd | Education | 2020 |
| Skandishack Ltd | Professional & scientific | 2020 |
| Skelwith Fold Caravan Park Limited | Hospitality | 1961 |
| Skerton Service Centre Limited | Wholesale & retail | 2025 |
| Skinzo Ltd. | Health & social care | 2019 |
| Skipton Street Luxury Apartments Ltd | Real estate | 2022 |
| Skjk Ltd | Health & social care | 2019 |
| Skjl Ltd | Real estate | 2024 |
| Sklingshot Ltd | Professional & scientific | 2024 |
| SKM Meds Ltd | Health & social care | 2015 |
| Skydrone Ltd | Manufacturing | 2025 |
| Skye Luxury Rentals Limited | Real estate | 2024 |
| Slate Marketing Limited | Professional & scientific | 2008 |
| Slayers INK Ltd | Other services | 2026 |
| Slice and Scoop Events Limited | Hospitality | 2025 |
| Slippy Holdings Limited | Financial services | 2022 |
| Slow Revolution Ltd | Information & communication | 2022 |
| Slyne Caravan Park Limited | Hospitality | 2019 |