| 34561 | S.M.P. | ZX81 16K | English |
| 43552 | SAMMS | ZX81 16K | English |
| 40502 | SCONNEX | ZX81 16K | English |
| 29283 | SKETCHPA | ZX81 16K | - |
| 35718 | SLR Venture | ZX81 16K | English |
| 29294 | SORTEER | ZX81 16K | Dutch |
| 29297 | SORTEER4 | ZX81 16K | German |
| 41499 | SPRF - Single Precision Prime Factorisation | ZX81 16K | English |
| 32052 | SRAM HR Ext. BASIC | ZX81 16K | English |
| 29259 | Sabotage | ZX81 16K | English |
| 38792 | Sabotagem | ZX81 16K | Portuguese |
| 39209 | Sales Ledger | ZX81 16K | English |
| 39725 | Salvage | ZX81 16K | English |
| 31784 | Salvo | ZX81 16K | - |
| 36823 | Samurai | ZX81 16K | Portuguese |
| 31785 | Samurai Warrior | ZX81 16K | - |
| 40554 | Santa's Helper | ZX81 16K | English |
| 41168 | Satellite | ZX81 16K | English |
| 41305 | Satellite Collector | ZX81 16K | English |
| 41055 | Satellites | ZX81 16K | English |