| P | # | Player | Born | Height | Weight | Contract | |
|---|---|---|---|---|---|---|---|
| D | Arthur Boka | 1984-04-02 | 166 | 65 | 2017-06-30 | ||
| D | Federico Dimarco | 1997-11-10 | 174 | 64 | |||
| D | Reto Ziegler | 1986-01-16 | 183 | 79 | |||
| M | Martin Zeman | 1989-03-28 | 175 | 64 | 2018-06-30 | ||
| M | Sébastien Wüthrich | 1990-05-29 | 180 | 73 | 2018-06-30 | ||
| F | Fousseyni Cissé | 1989-07-17 | 195 | - | Loan | ||
| F | Robert Acquafresca | 1987-09-11 | 184 | 70 |
| Date | Player | From | To | Status | Src |
|---|---|---|---|---|---|
| 12.Aug | Patrick Luan (F) | FC Sion | Örebro SK | Confirmed | |
| 25.Aug | Edimilson Fernandes (F) | FC Sion | West Ham United | Confirmed | |
| 12.Jul | Arthur Boka (D) | Málaga CF | FC Sion | Confirmed | |
| 10.Jun | Martin Zeman (M) | AC Sparta Prag | FC Sion | Confirmed | |
| 2.Feb | Reto Ziegler (D) | Free Agent | FC Sion | Confirmed | |
| 25.Jun | Andreas Hedström (D) | FC Sion | Djurgårdens IF | Rumour | |
| 16.Jun | Kyle Lafferty (F) | FC Sion | USC Palermo | Confirmed | |
| 30.Jan | Kyle Lafferty (F) | FC Sion | USC Palermo | Doubtful | |
| 3.Jan | José Goncalves (D) | FC Sion | New England Revolution | Confirmed | |
| 15.Jun | Gennaro Gattuso (M) | Free Agent | FC Sion | Confirmed |