| Rohir Oy | Agriculture & fishing | 2010 |
| Room304 Oy | Other services | 2018 |
| Rotyx Oy | Manufacturing | 2006 |
| Ruokahaavi Oy | Wholesale & retail | 2025 |
| Ruokakeidas San Polo Ky | | 1992 |
| Rutv Oy | Information & communication | 2009 |
| S & M Autohuolto Osk | Other services | 2015 |
| S&Z Partners Oy | Hospitality | 2022 |
| S-Kojeisto Oy | Manufacturing | 2025 |
| Saurak OY | Construction | 2006 |
| Savonlinnan HB Metalli OY | Manufacturing | 2021 |
| SFD Hair Oy | Other services | 1982 |
| SGS Sports Gear Service Oy | Arts & recreation | 1995 |
| SK9 Partners Oy | Real estate | 2025 |
| SKO-palvelut Oy | Administrative & support | 2016 |
| SL Travels Oy | Administrative & support | 2015 |
| SLN Nahkatavara Oy | Wholesale & retail | 1972 |
| SLN Service Oy | Administrative & support | 2023 |
| SN Metal Oy | Manufacturing | 2024 |
| SPE-vuokraus, avoin yhtiö | Administrative & support | 1992 |
| SPK Welding Oy | Manufacturing | 2019 |
| SSP Group Oy | Construction | 2002 |
| SSP LVI Oy | Construction | 1993 |
| ST Legal Oy | Professional & scientific | 2023 |
| ST Liikenne Oy | Transport & logistics | 2019 |
| SaPKo Hockey Oy | Arts & recreation | 2023 |
| Saariston Suleima Oy | Real estate | 1995 |
| Sailmaa Oy | Administrative & support | 1990 |
| Saimaa Igloos Oy | Hospitality | 2021 |
| Saimaa Power Oy | Construction | 2007 |
| Saimaa Product Oy | Manufacturing | 2022 |
| Saimaa Sales Oy | Financial services | 2021 |
| Saimaa Travel Finland Oy | Administrative & support | 2025 |
| Saimaa Yacht Charters Oy | Administrative & support | 2020 |
| Saimaa Yacht Store Oy | Arts & recreation | 2011 |
| Saimaan Aalto Oy | Wholesale & retail | 2019 |
| Saimaan Henkilöstö Oy | Administrative & support | 2022 |
| Saimaan Kauppakiinteistöt Oy | Real estate | 2025 |
| Saimaan Laatuhuvilat Oy | Construction | 2001 |
| Saimaan MH-Kuljetus Oy | Transport & logistics | 2022 |
| Saimaan Marjamarkkinointi Oy | Manufacturing | 2009 |
| Saimaan Metalli ja Telakointi Oy | Manufacturing | 2009 |
| Saimaan Monitoimi Oy | Professional & scientific | 1998 |
| Saimaan Rahtikuljetus Ky | Transport & logistics | 1976 |
| Saimaan Rakentajat Oy | Construction | 2017 |
| Saimaan Siima Oy | Administrative & support | 2007 |
| Saimaan Solmu Ky | Administrative & support | 1995 |
| Saimaan Vesistörakentajat Oy | Construction | 2021 |
| Saimaan Vesityö Oy | Construction | 1992 |
| Saimaan Vesselit Oy | Construction | 2026 |
| Saimaan Vuokravenho Oy | Administrative & support | 1996 |
| Saimaanrauta Oy | Wholesale & retail | 2007 |
| Saimaanvalo Oy | Education | 2023 |
| Saimaanvarastot Oy | Real estate | 2018 |
| Saimart Oy | Wholesale & retail | 1995 |
| Salon MT Ky Maire Tiittala | Other services | 1988 |
| Salon Pinna Oy | Other services | 2014 |
| Sami-Palvelut Oy | Education | 2015 |
| Samun Taksit Oy | Transport & logistics | 2018 |
| Sataman PodoFysio Oy | Health & social care | 2018 |
| Sauron Entertainment Oy | Arts & recreation | 2024 |
| SavoFit Oy | Arts & recreation | 2015 |
| Savoir experience Oy | Hospitality | 2026 |
| Savolan Kiinteistöosakeyhtiö | Real estate | 1996 |
| Savon AC/DC Oy | Construction | 2019 |
| Savon Camping Oy | Hospitality | 2023 |
| Savon MA-Rakennus Oy | Construction | 2011 |
| Savon Marttapalvelut Oy | Administrative & support | 2013 |
| Savon Palvelut oy | Construction | 2012 |
| Savon Pilke Oy | Agriculture & fishing | 2024 |
| Savon Putkitaito Oy | Construction | 2018 |
| Savon Satalaite Oy | Manufacturing | 1998 |
| Savon Sukitus Oy | Construction | 2018 |
| Savon Suuhygienia Oy | Health & social care | 2025 |
| Savon Taitajat Oy | Administrative & support | 2011 |
| Savon Taitotyöt Oy | Construction | 2019 |
| Savon Työpalvelu Oy | Construction | 2014 |
| Savon sisustajat Oy | Wholesale & retail | 2026 |
| Savonia Lakes Oy | Construction | 1993 |
| Savonlinna Camping Oy | Hospitality | 2015 |
| Savonlinna City Run Oy | Arts & recreation | 2019 |
| Savonlinna International Education Center Oy Ltd | Education | 2021 |
| Savonlinna Med Oy | Manufacturing | 2001 |
| Savonlinnan Aarrearkku Oy | Wholesale & retail | 2018 |
| Savonlinnan Asunnontuotanto osakeyhtiö | Real estate | 1949 |
| Savonlinnan Auto-Opisto Oy | Education | 1988 |
| Savonlinnan BLC-osuuskunta | Information & communication | 1921 |
| Savonlinnan Burger Oy | Hospitality | 2004 |
| Savonlinnan City-Kukka M & J Viinanen | Wholesale & retail | 1995 |
| Savonlinnan Eläinlääkäriasema Oy | Professional & scientific | 2018 |
| Savonlinnan Erikoispohjalliset Oy | Manufacturing | 2023 |
| Savonlinnan Hankekehitys Oy | Professional & scientific | 2013 |
| Savonlinnan Hautaus- ja Juhlapalvelu Oy | Other services | 2008 |
| Savonlinnan Herkku Pekka Pullapuoti Oy | Wholesale & retail | 1990 |
| Savonlinnan Hirsityöt Oy | Construction | 2015 |
| Savonlinnan Honkaranta Oy | Hospitality | 1986 |
| Savonlinnan Isännöintikeskus Oy | Real estate | 1992 |
| Savonlinnan Jäähalli Osakeyhtiö | Arts & recreation | 1986 |
| Savonlinnan Kiviveistämö Rautiainen Oy | Manufacturing | 1980 |
| Savonlinnan Ko-Ra-Su Ky | | |