| ITF M25 - Santa Margherita | 04/19 14:10 | 25 | Giovanni Fonio v Toby Martin | 6-0,6-2 | |
| ITF M25 - Santa Margherita | 04/12 16:15 | 25 | [489] Matteo Gigante v Giovanni Fonio [454] | 4-6,7-5,7-6 | |
| Challenger - Sanremo | 04/04 08:00 | 19 | [455] Giovanni Fonio v Mate Valkusz [402] | 7-5,4-6,4-6 | |
| Challenger - Sanremo | 04/03 09:30 | 14 | [416] Giovanni Fonio v Alexander Weis [468] | 6-4,6-4 | |
| Challenger - Lugano | 03/27 12:35 | 14 | [299] Ruben Bemelmans v Giovanni Fonio [416] | 7-5,6-4 | |
| ITF M25 - Opatija | 03/22 10:45 | 25 | [489] Francesco Passaro v Giovanni Fonio [414] | 6-0,4-6,6-2 | |
| ITF M25 - Rovinj | 03/15 12:35 | 25 | [362] Ergi Kirkin v Giovanni Fonio [414] | 6-4,7-6 | |
| ITF M25 - Porec | 03/09 10:45 | 25 | [335] Filip Misolic v Giovanni Fonio [414] | 7-6,6-4 | |
| ITF M25 - Antalya | 02/26 09:15 | 27 | [367] Daniel Michalski v Giovanni Fonio [408] | 6-3,4-6,7-5 | |
| ITF M25 - Antalya | 02/25 12:30 | 26 | Giovanni Fonio v Andrea Picchione | Retired | |
| ITF M25 - Antalya | 02/22 11:00 | 25 | Togan Tokac v Giovanni Fonio | 1-6,1-6 | |
| ITF M25 - Antalya | 02/15 11:25 | 25 | [330] Miljan Zekic v Giovanni Fonio [412] | 6-2,6-4 | |
| ITF M15 - Antalya | 01/29 15:15 | 27 | [411] Giovanni Fonio v Corentin Denolly [450] | 6-7,2-6 | |
| ITF M15 - Antalya | 01/29 11:30 | 26 | Giovanni Fonio v S Mert Ozdemir | 6-2,6-2 | |
| ITF M15 - Antalya | 01/28 09:00 | 25 | Giovanni Fonio v Juan P Canas Garcia | 7-5,6-2 | |
| ITF M15 - Antalya | 01/23 08:50 | 29 | [479] Cezar Cretu v Giovanni Fonio [411] | 1-6,4-6 | |
| ITF M15 - Antalya | 01/22 10:00 | 28 | Giovanni Fonio v Davide Galoppini | 6-1,6-2 | |
| ITF M15 - Antalya | 01/21 13:00 | 27 | Paul Woerner v Giovanni Fonio | 1-6,3-6 | |
| ITF M15 - Antalya | 01/20 15:00 | 26 | Calin Manda v Giovanni Fonio | 4-6,3-6 | |
| ITF M15 - Antalya | 01/19 12:40 | 25 | Aleksandar Tomas v Giovanni Fonio | 2-6,2-6 | |
| Challenger - Antalya | 12/11 10:00 | 28 | [409] Oleg Prihodko v Giovanni Fonio [441] | 1-6,6-1,6-3 | |
| Challenger - Antalya | 12/10 07:00 | 27 | [441] Giovanni Fonio v Nick Hardt [350] | 7-6,6-2 | |
| Challenger - Antalya | 12/09 09:25 | 26 | [264] Ryan Peniston v Giovanni Fonio [441] | 6-1,4-6,4-6 | |
| Challenger - Antalya | 12/08 12:30 | 25 | [466] Jakub Paul v Giovanni Fonio [441] | 1-6,0-6 | |
| Challenger - Antalya | 11/29 07:30 | 14 | Marsel Ilhan v Giovanni Fonio | 6-4,3-6,6-4 | |
| Challenger - Napoli | 10/11 08:00 | 14 | [303] Javier Barranco Cosano v Giovanni Fonio [437] | 7-5,6-3 | |
| ITF M15 - Platja D'Aro | 10/09 09:00 | 28 | [437] Giovanni Fonio v Jose Fco. Vidal Azorin [476] | 3-6,4-6 | |
| ITF M15 - Platja D'Aro | 10/08 10:00 | 27 | Giovanni Fonio v Maxime Chazal | 6-3,6-2 | |
| ITF M15 - Platja D'Aro | 10/07 13:35 | 26 | Giovanni Fonio v Manish Sureshkumar | 6-0,6-1 | |
| ITF M15 - Platja D'Aro | 10/06 10:15 | 25 | Giovanni Fonio v Vitali Shvets | 6-4,6-0 |
Giovanni Fonio (born 7 May 1998) is an Italian tennis player. He took his first steps in tennis at the age of 5, at the Piazzano tennis club in Novara.
Fonio has a career high ATP singles ranking of 274 achieved on 4 Dicember 2023. He also has a career high doubles ranking of 406 achieved on 15 January 2024.
Fonio has won 2 ATP Challenger doubles title: at the 2023 Internazionali di Tennis del Friuli Venezia Giulia with Francesco Forti and at the 2021 Antalya Challenger III with Riccardo Bonadio.
The greatest victory achieved by Giovanni was certainly during the Yokkaichi Challenger in Japan, on 30 November 2023, when he beat the then top 100 player Yosuke Watanuki in 3 sets (3-6 / 6-2 / 7-5).
An important presence in high-level tournaments was certainly in May 2022 at the qualifiers at the Internazionali d’Italia, unfortunately he lost against Emil Ruusuvuori 2-1 (4-6 / 7-6 / 3-6).