- Sylen
- Synod
- Sageston
- Saint Margaret’s Island
- Saint Nicholas
- Saltney
- Sardis
- Sarn
- Sarn
- Sarn Bach
- Sarnau
- Saron
- Saron
- Seion
- Sheep Island
- Shotton
- Sigingstone
- Six Bells
- Skokholm Island
- Skomer Island
- Sling
- Soar
- Southsea
- St Athan
- St Bride's Netherwent
- St Catherine's Island
- St. Dogmaels
- St George
- Star
- Stepaside