| Societé de développement de l'exportation de Longueuil | Business Centres | facebook.com |
| Société de Développement des Arts et de la Culture de Longueuil (S O D A C) | Arts & Cultural Organizations & Centres | facebook.com |
| Société historique du Marigot | Tout Enseignement et savoir, Tout Informations générales | marigot.ca |
| Sofa Nova Design | Car Washes | — |
| Softinfo | Life Sciences and Health Technologies (LSHT), Tout Entreprises et services | www2.softinfo.ca |
| Sogel | Tout Entreprises et services | sogel.ca |
| Sogémap inc. | Tout Entreprises et services | sogemap.com |
| Soins Reiki Par Micheline Faccone | Alternative Health | facebook.com |
| Soins Thérapeutiques Kassis | Massage Therapy | soinstherapeutiqueskassis.com |
| Solmatech Inc | Analytical & Testing Laboratories | — |
| Solution Beauté | Beauty & Fitness, Hairdressers & Beauty Salons | — |
| Solution Comfort | Air Conditioning Contractors | facebook.com |
| Solution Web Wave-Tech.ca | Advertising Agencies | — |
| Somis Inc | Information Technologies (IT) | somis.fr |
| Sophie Périgny Coiffure | Beauty & Fitness, Hairdressers & Beauty Salons | facebook.com |
| Sorajay Pieds Et Mains | Beauty & Fitness, Hairdressers & Beauty Salons | facebook.com |
| Soto The Barber | Barbers, Men's Hairdressers & Barber Shops | — |
| SOVRA | Tout Entreprises et services, Tout Informatique et internet | sovra.com |
| Spa Concept Exylium | Beauty & Fitness, Hairdressers & Beauty Salons | — |
| Spa Victoria | Beauty & Fitness, Hairdressers & Beauty Salons | spavictoria.ca |
| Spas & Solarium Dépôt Inc | Health and Beauty | — |
| Specmont Inc. | Tout Entreprises et services | krytex.com |
| Spectre Sonore | Tout Entreprises et services | spectre-entertainment.com |
| SPI Communications Inc | Advertising Agencies | — |
| Spline Technologies Corp. | Tout Informatique et internet | remotedebugger.com |
| Spécialiste en Spray | Painters | specialisteenspray.com |
| Spécialités Johanne Ranger | Cakes | — |
| Spécifik Performance Longueuil | Fitness Gyms | — |
| SQDC - Longueuil - Place Longueuil | Boutiques | placelongueuil.com |
| St Mark's Anglican Church | Churches & Other Places of Worship | stmarkslongueuil.ca |
| St Maurice François | Health Services | — |
| St-Laurent Et Associés | Bookkeeping | — |
| St-Mary's Elementary School | Tout Enseignement et savoir | rsb.qc.ca |
| Staples Avantage | Information Technologies (IT) | staplesadvantage.ca |
| Starik Salon de Coiffure | Beauty & Fitness, Hairdressers & Beauty Salons | facebook.com |
| STAT Timing | Tout Entreprises et services | stat-timing.com |
| Statik Salon De Coiffure | Beauty & Fitness, Hairdressers & Beauty Salons | — |
| Ste-Croix Julie | Dentists | — |
| Sterling 925 | Boutiques | — |
| Stmi Service Technique Micro Informatique | Computer Networking | — |
| Structure acier VIP Inc | Tout Entreprises et services | aciervip.com |
| Studio Democlic | Tout Entreprises et services | democlic.com |
| Subversives Distillers | Chemicals | facebook.com |
| Sud Auto Electrique Inc | Alternators & Starters | sudelectriqueinc.com |
| Sun Sun Restaurant | Chinese Food Restaurants | facebook.com |
| SunTech Recycle Inc. | Tout Entreprises et services, Tout Informatique et internet | suntechrecycle.com |
| Suntek | Tout Entreprises et services | suntekawnings.com |
| Supra Z | Auto Part Manufacturers & Wholesalers | supraz.ca |
| Suspension Longueuil-AUTOPLACE | Car Brake Service | suspensionslongueuil.com |
| Suzanne Couture | Couture, COUTURE | — |
