| Challenger Genoa | 09/02 08:00 | 25 | [243] Alvaro Guillen Meza v Giovanni Fonio [407] | 6-3,3-6,6-4 | |
| Challenger Genoa | 09/01 09:45 | 19 | [407] Giovanni Fonio v Gabriele Pennaforti [472] | 0-6,6-4,4-6 | |
| Challenger Genoa | 08/31 14:05 | 14 | Giovanni Fonio v Parikshit Somani | 6-3,6-2 | |
| Challenger Genoa | 08/31 12:00 | 14 | Giovanni Fonio v Jacopo Vasami | CANC | |
| Challenger Como | 08/29 10:20 | 26 | [158] Nicolai Budkov Kjaer v Giovanni Fonio [407] | 6-4,7-6 | |
| Challenger Como | 08/26 11:05 | 25 | [416] Federico Bondioli v Giovanni Fonio [407] | 2-6,6-3,3-6 | |
| Challenger Como | 08/25 10:25 | 19 | [407] Giovanni Fonio v Jacopo Vasami [387] | 6-4,6-2 | |
| Challenger Como | 08/24 12:00 | 14 | Giovanni Fonio v Rocco Piatti | 6-3,6-4 | |
| ITF M25 Lesa | 08/22 18:00 | - | Lorenzo Carboni v Giovanni Fonio | 6-2,5-3 | |
| ITF M25 Lesa | 08/21 10:00 | - | Niccolo Ciavarella v Giovanni Fonio | 5-7,0-6 | |
| ITF M25 Lesa | 08/20 10:30 | - | Thomas Gerbaud v Giovanni Fonio | 3-6,3-6 | |
| ITF M25 Bolzano | 07/29 13:06 | - | [431] Giovanni Oradini v Giovanni Fonio [383] | 7-6,6-7,6-4 |
Giovanni Fonio (born 7 May 1998) is an Italian tennis player.
Fonio has a career high ATP singles ranking of world No. 269 achieved on 29 January 2024. He also has a career high doubles ranking of No. 406 achieved on 15 January 2024.
Fonio has won 2 ATP Challenger doubles title: at the 2021 Antalya Challenger III with Riccardo Bonadio and at the 2023 Internazionali di Tennis del Friuli Venezia Giulia with Francesco Forti.
In May 2022, at the qualifiers at the Internazionali d’Italia he lost to Emil Ruusuvuori.
On 30 November 2023, at the Yokkaichi Challenger in Japan, he defeated the then top 100 player Yosuke Watanuki in 3 sets.