| Skyrora Ventures | |
| Skyscanner Ltd | |
| SLA Pharma (UK) Ltd | |
| Slamcore Ltd | |
| SlashData | |
| Slate | |
| Slater Marketing Group Ltd | |
| Sleeky Web Design & Print Ltd | |
| Sleeping Giant Media | Kent |
| Sleepy Frog Designs | |
| Sliced Ltd | West Sussex |
| Slingshot Search Ltd | |
| Slingshot Simulations Ltd | |
| SliQTools | Shropshire |
| Slitherine Software UK Ltd | Surrey |
| sllip.io | |
| SLNG Ltd | |
| Sloneek | |
| Sloomedia | Nottinghamshire |
| SLS Optics Ltd | Isle of Man |
| Sly Engine AI | |
| SMACK Digital Ltd | |
| Small Batch Design | West Midlands |
| Small Business Web Designer | |
| Small Business Websites | Cardiff |
| Small Robot Company | |
| Small Spark Space Systems Ltd | |
| small-media-large | |
| small-media-large | |
| SmallGiants Services Ltd | |
| SmallSEOTools.com | |
| Smallworld IT (UK) Ltd | Surrey |
| Smart Acoustics Ltd | |
| Smart Advertisement | |
| Smart Buildings | |
| Smart Coders Pvt Ltd | |
| Smart Communications | |
| Smart Computers & Networks Ltd | South Yorkshire |
| Smart Computers Ltd | Gloucestershire |
| Smart Connect Ltd | Dorset |
| Smart Container Company Ltd | |
| Smart Data Foundry | |
| Smart DB Ltd | |
| Smart DCC Ltd | |
| Smart Electronics | |
| Smart Fabric Ltd | |
| Smart Fix Edinburgh | |
| Smart Flow | |
| Smart Homes | |
| Smart Host Group Ltd | |