- Safmarine
- Saga Cruises
- Sally Ferries
- Sandbanks Ferry
- Scandlines
- Schreiber, Otto W.A.
- Seabourn Cruise Line
- Seadream Yacht Club
- SeaFrance
- Sealink see British Railways
- Seaspeed see British Railways
- Seatrade
- Seetouristik
- Semester At Sea
- SGV (Lake Lucerne)
- Shaw Savill & Albion
- Silja Line
- Silverseas Cruises
- SIOSA
- Sitmar Line
- SNAV
- SNCF
- SNCM / CGTM
- Solent & Wightline Cruises
- Solent Towage
- South East & Chatham Railway
- Southern Railway
- St. Helena Shipping
- Star Clippers
- Star Cruises
- Stena Line
- Stephenson Clarke
- Streckfus Steamers
- Strintzis Lines
- Sud-Atlantique, Cie
- Sun Cruises
- Sun Line
- Superfast Ferries
- Svea Line
- Svitzer Marine
- Swan Hellenic
- Swansea-Cork Ferries
- Swedish America Line
- Swedish Lloyd
- Sydney Harbour Ferries