- Skokholm Island
- Skomer Island
- Sling
- Snead
- Soar
- Solva
- South Beach
- South Cornelly
- Southerndown
- Southgate
- Southsea
- Spittal
- Square and Compass
- St Athan
- St Bride's Netherwent
- St Catherine's Island
- St. Dogmaels
- St George
- Stackpole
- Star
- Star
- Staylittle
- Stepaside
- Stepaside
- Steynton
- Strata Florida
- Stryd-y-Facsen
- Sudbrook
- Sully
- Sully Island