| Sacha, Oliver | IHK | | |
| Salzmann, Christiane | Wendepunkt | | |
| Sanovec, Victor | | | |
| Sartorius, Friedrich | FDP | | |
| Sauer, Britta | | | |
| Sauer, Christin | BÜNDNIS90/DIE GRÜNEN | | |
| Schaadt, Katrin | BÜNDNIS 90/DIE GRÜNEN | | |
| Schebitz, Tino | | | |
| Scheer, Maren | | | |
| Scheib, Jens | VOLT | | |
| Schek, Franz-Josef | SPD | | |
| Schenk, Dr. Peter | ÖDP | | |
| Schinke, Dr. Holger | ÖDP | | |
| Schlag, Stefan | Universität Mainz | | |
| Schleutermann, Natalie | Luftfahrtverein | | |
| Schlitz-Salvado, Doris | | | |
| Schlunke, Sven | | | |
| Schmelzer, Ricarda | | | |
| Schmich-Gehbauer, Gaby | IFD | | |
| Schmitt, Ludwig Philipp | | | |
| Schmitt, Rolf | | | |
| Schmitz, Markus | SPD | | |
| Schmöller, Jana | SPD | | |
| Schneider, Matthias | | | |
| Schuster, Regine | | | |
| Schwaben, Dr. Julia | | | |
| Schwarting, Prof. Dr. Gunnar | SPD | | |
| Schwarzer, Torsten | CDU | | |
| Schweitzer, Tilman | Volt | | |
| Schweizer, Johannes | | | |
| Schüler, Alban | CDU | | |
| Schüler, Armin | CDU | | |
| Schüler, Christian | CDU | | |
| Schüler, Simone | CDU | | |
| Schütz, Kai | ÖDP | | |
| Schäfer, Landrätin Dorothea | | | |
| Schäfer, Herbert | CDU | | |
| Seckler-Classen, Monja | Ev. Diakoniezentrum ZOAR | | |
| Seddig, Ina | Architektenkammer RP | | |
| Seib-Marx, Astrid | | | |
| Senger, Frank | AfD | | |
| Sieben, Markus | CDU | | |
| Siebner, Claudia | CDU | | |
| Simon, Darius | AfD | | |
| Simonis, Hannah | DIE LINKE | | |
| Spancken, Phillip | ÖDP | | |
| Speckmann, Eberhard | DIE LINKE | | |
| Sperb, Philipp | | | |
| Stadtfeld, Thomas | Caritasverband | | |
| Stahl, Carlotta | DIE LINKE | | |
| Stahl, Christian | DIE LINKE. | | |
| Stahlheber, Veith | DIE LINKE | | |
| Steffen, Markus | CDU | | |
| Steffen-Boxhorn, Andrea | ÖDP | | |
| Stegner, Naomi | Netz G | | |
| Steiner, Benjamin | AfD | | |
| Steiner, Benjamin | AfD | | |
| Steinke, Dr. Karsten | ÖDP | | |
| Steinkrüger, Janina | | | |
| Steinkrüger, Janina | | | |
| Stenner, Paul | SPD | | |
| Stockschläder, Hermann | CDU | | |
| Stolz, Andreas | DRK Kreisverband Mainz-Bingen | | |
| Strauch, Michael | AfD | | |
| Stritter, Stephan | AfD | | |
| Strotkötter, Gerhard | SPD | 05.09.2024 | bis 05.09.2024 |
| Stufler, Erwin | FREIE WÄHLER | | |
| Stumpf, Kerstin | Mainzer Stadtwerke AG | | |
| Sturniolo-Westenberger, Michaela | SPD | | |
| Sühling, Michael | | | |
| Süssenberger, Falk | | | |
