S
- Samson
- San Pacific International Inc
- SandJ Products
- SAS Safety Corp.
- Scandvik
- Scanstrut
- Schmitt & Ongaro
- Scotsco Inc
- Scotty
- Scrubbis
- Sea Catch
- Sea Hawk
- Sea Shield Marine
- Sea-Dog
- Sea-Fire
- SeaBear Wild Salmon
- SeaChoice
- SeaForce
- SeaForce Teak
- Seaguar
- Seakamp Engineering
- SeaLand
- SeaMaster Lights
- Seapower
- SeaSense
- Seasonal Marketing
- SeaStar Solutions
- SeaTeak
- Seats Incorporated
- Seattle Chocolates
- Seattle Forging and Tool / Fife Forge
- Seattle Pump
- Seattle Sports Company
- Seattle Tarp
- Selectech
- Seloc
- Sen-Dure
- Servus
- Sevylor
- Shakespeare
- Sharkhide
- Sharp
- Shaw Development LLC
- Sherwood
- Shields Marine Hose
- Shimano
- Shoretex
- Showa
- Shurflo
- Shurhold
- Side-Power
- Sierra / Seastar Solutions
- Sika Corporation
- Sikkens
- Silver Horde
- Sinox International
- Skretting
- Skyco, The Skybryte Co.
- Smak Plastics
- Smart Tabs
- SmartPlug
- Smartwool
- Smith's Products
- Smokehouse Products
- Snappy Boat Care
- So-Pac
- Solas
- SMI
- Spectro Wire & Cable
- Spencer Aircraft
- SPI Home
- Sport Marine Technologies
- SportsStuff Towables
- Sprayco
- Springfield Marine
- Square One Maps
- Sta-Bil
- Standard Horizon
- Starbrite Distributing
- Stearns
- Sterndrive Engineering
- Stewart Warner
- Stingray
- STLHD
- Stohlquist
- Stormline
- Stormr
- Sudbury
- Sugatsune
- Sun-Flow
- Suncoast of America
- Suncor Stainless
- Survitec Survival Products Inc
- Swivl-Eze
- Synco Chemical Corporation
- System Three Resins
- Superbait
- Sur-Shade