Guglielmo Costantini has been a Napoli's Italian defender. In 4 seasons he played 27 matches. He won 1 trophy.
| Season | Year | | Caps | Goals | | Caps | Goals | | Caps | Goals | | Caps | Goals | It L | It C | Eu C | |
|---|
| 1958-59 | 58-59 |
| 15 | 0 | A | 14 | 0 | IC | 1 | 0 | - | 0 | 0 | 14 (0) | 1 (0) | 0 (0) | |
| 1959-60 | 59-60 |
| 6 | 0 | A | 4 | 0 | IC | 0 | 0 | CdA | 2 | 0 | 4 (0) | 0 (0) | 2 (0) | |
| 1960-61 | 60-61 |
| 5 | 0 | A | 5 | 0 | IC | 0 | 0 | - | 0 | 0 | 5 (0) | 0 (0) | 0 (0) | |
| 1961-62 | 61-62 |
| 1 | 0 | B | 1 | 0 | IC | 0 | 0 | - | 0 | 0 | 1 (0) | 0 (0) | 0 (0) | |
| |
| 27 | 0 | | 24 | 0 | | 1 | 0 | | 2 | 0 | 24 (0) | 1 (0) | 2 (0) | |