- Saint John
- Salmon Creek
- Sammamish
- Santiago
- Satsop
- Satus
- Seabeck
- SeaTac
- Seattle
- Sedro-Woolley
- Sekiu
- Selah
- Sequim
- Shaker Church
- Shelton
- Shoreline
- Silvana
- Silver Firs
- Silverdale
- Sisco Heights
- Skamokawa Valley
- Skokomish
- Skykomish
- Smokey Point
- Snohomish
- Snoqualmie
- Snoqualmie Pass
- Soap Lake
- South Bend
- South Cle Elum
- South Hill
- South Prairie
- South Wenatchee
- Southworth
- Spanaway
- Spangle
- Spokane
- Spokane Valley
- Sprague
- Springdale
- Stanwood
- Starbuck
- Startup
- Steilacoom
- Steptoe
- Stevens Pass Resort
- Stevenson
- Stimson Crossing
- Sudden Valley
- Sultan
- Sumas
- Summit
- Summit View
- Summitview
- Sumner
- Sunnyside
- Sunnyslope
- Suquamish
- Swede Heaven
