| Doubles | |
|---|---|
| 2021 Internazionali di Tennis Città di Trieste | |
| Champions |  Orlando Luz Felipe Meligeni Alves |
| Runners-up |  Antoine Hoang Albano Olivetti |
| Score | 7–5, 6–7(6–8), [10–5] |
Ariel Behar and Andrey Golubev were the defending champions [1] but chose not to defend their title.
Orlando Luz and Felipe Meligeni Alves won the title after defeating Antoine Hoang and Albano Olivetti 7–5, 6–7(6–8), [10–5] in the final.
Orlando Luz / Felipe Meligeni Alves (champions) Antoine Hoang / Albano Olivetti (final) Dan Added / 
Vitaliy Sachko (semifinals)
Martín Cuevas / 
Andrea Pellegrino (quarterfinals)| First round | Quarterfinals | Semifinals | Final | ||||||||||||||||||||||||
| 1 | O Luz F Meligeni Alves | w/o | |||||||||||||||||||||||||
 D Džumhur N Fatić | 1 | O Luz F Meligeni Alves | 6 | 7 | |||||||||||||||||||||||
M Bortolotti  B Lock | 65 | 6 | [7] |  A Dubrivnyy  D Yevseyev | 4 | 5 | |||||||||||||||||||||
| A Dubrivnyy D Yevseyev | 77 | 2 | [10] | 1 | O Luz F Meligeni Alves | 6 | 3 | [10] | |||||||||||||||||||
| F Forti G Zeppieri | 4 | 6 | [3] | ||||||||||||||||||||||||
| 4 | M Cuevas A Pellegrino | 3 | 2 | ||||||||||||||||||||||||
| F Forti G Zeppieri | 4 | F Forti G Zeppieri | 6 | 6 | |||||||||||||||||||||||
| WC | Pietro Pampanin Daniele Valentino | 1r | 1 | O Luz F Meligeni Alves | 7 | 66 | [10] | ||||||||||||||||||||
R Bonadio  M Vrbenský | 6 | 6 | 2 | A Hoang A Olivetti | 5 | 78 | [5] | ||||||||||||||||||||
| PR | A Motti J Ocleppo | 1 | 2 | R Bonadio M Vrbenský | 2 | 3 | |||||||||||||||||||||
| WC | Matteo Marfia Augusto Virgili | 3 | 2 | 3 | D Added V Sachko | 6 | 6 | ||||||||||||||||||||
| 3 | D Added V Sachko | 6 | 6 | 3 | D Added V Sachko | 6 | 5 | [7] | |||||||||||||||||||
| WC |  R Bertola G Fonio | 7 | 6 | 2 | A Hoang A Olivetti | 0 | 7 | [10] | |||||||||||||||||||
 A Collarini P Sakamoto | 5 | 3 | WC | R Bertola G Fonio | 6 | 2 | [7] | ||||||||||||||||||||
| H Casanova C Ugo Carabelli | 3 | 3 | 2 | A Hoang A Olivetti | 4 | 6 | [10] | ||||||||||||||||||||
| 2 | A Hoang A Olivetti | 6 | 6 | ||||||||||||||||||||||||
Andrés Artuñedo and David Pérez Sanz were the defending champions but only Artuñedo chose to defend his title, partnering Sergio Martos Gornés. Artuñedo lost in the first round to Andreas Siljeström and Andrea Vavassori.
Hugo Dellien and Guillermo Durán were the defending champions but only Dellien chose to defend his title, partnering Federico Zeballos. Dellien and Zeballos withdrew before their quarterfinal match.
Guillermo Durán and Roberto Quiroz were the defending champions but only Quiroz chose to defend his title, partnering Yannick Hanfmann. Quiroz lost in the first round to Luis David Martínez and Felipe Meligeni Alves.
Guido Andreozzi and Guillermo Durán were the defending champions but chose not to defend their title.
Guido Andreozzi and Guillermo Durán were the defending champions but only Durán chose to defend his title, partnering Mariano Kestelboim. Durán lost in the first round to Facundo Mena and Camilo Ugo Carabelli.
This was the first edition of the tournament. It was originally scheduled to take place in Florianópolis but was relocated to São Paulo and took the São Paulo Challenger de Tênis namesake.
Orlando Luz and Rafael Matos were the defending champions but only Matos chose to defend his title, partnering João Menezes. Matos withdrew from the tournament before his quarterfinal match.
Franco Agamenone and Fernando Romboli were the defending champions but chose not to defend their title.
Sadio Doumbia and Fabien Reboul were the defending champions and successfully defended their title, defeating Guido Andreozzi and Guillermo Durán 7–5, 6–3 in the final.
Rafael Matos and João Menezes were the defending champions but chose not to defend their title.
Sander Arends and David Pel were the defending champions but chose not to defend their title.
The 2021 Internazionali di Tennis Città di Trieste was a professional tennis tournament played on clay courts. It was the 2nd edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Trieste, Italy between 26 July and 1 August 2021.
Radu Albot and Enrique López Pérez were the defending champions but chose not to defend their title.
Andre Begemann and Florin Mergea were the defending champions but chose not to defend their title.
Romain Arneodo and Hugo Nys were the defending champions but only Arneodo chose to defend his title, partnering Quentin Halys. Arneodo lost in the quarterfinals to Antoine Hoang and Kyrian Jacquet.
This was the first edition of the tournament.
Sadio Doumbia and Fabien Reboul were the defending champions but chose not to defend their title.
This was the first edition of the tournament and was part of the 2022 Legión Sudamericana.
Orlando Luz and Felipe Meligeni Alves were the defending champions but only Meligeni Alves chose to defend his title, partnering Marcelo Demoliner. Meligeni Alves lost in the quarterfinals to Luciano Darderi and Fernando Romboli.
Orlando Luz and Felipe Meligeni Alves were the defending champions but only Meligeni Alves chose to defend his title, partnering Marcelo Demoliner. Meligeni Alves lost in the quarterfinals to Marco Bortolotti and Sergio Martos Gornés.