| Doubles | |
|---|---|
| 2021 Challenger de Santiago | |
| Champions |  Luis David Martínez  Gonçalo Oliveira |
| Runners-up |  Rafael Matos Felipe Meligeni Alves |
| Score | 7–5, 6–1 |
Franco Agamenone and Fernando Romboli were the defending champions [1] but chose not to defend their title.
Luis David Martínez and Gonçalo Oliveira won the title after defeating Rafael Matos and Felipe Meligeni Alves 7–5, 6–1 in the final.
Luis David Martínez / Gonçalo Oliveira (champions) Rafael Matos / Felipe Meligeni Alves (final)
Sergio Galdós / 
Facundo Mena (semifinals) Orlando Luz / Renzo Olivo (first round)| First round | Quarterfinals | Semifinals | Final | ||||||||||||||||||||||||
| 1 | LD Martínez G Oliveira | 6 | 6 | ||||||||||||||||||||||||
 B Arias F Zeballos | 6 | 6 | B Arias F Zeballos | 4 | 3 | ||||||||||||||||||||||
| WC |  Hanamichi Carvajal Benjamín Torres | 2 | 4 | 1 | LD Martínez G Oliveira | 6 | 65 | [10] | |||||||||||||||||||
| 4 | O Luz R Olivo | 0 | 5 |  M Cuevas JP Varillas | 3 | 77 | [3] | ||||||||||||||||||||
| M Cuevas JP Varillas | 6 | 7 | M Cuevas JP Varillas | 6 | 6 | ||||||||||||||||||||||
| Víctor Núñez G Villanueva | 3 | 2 |  G Blancaneaux  K Coppejans | 2 | 4 | ||||||||||||||||||||||
| G Blancaneaux K Coppejans | 6 | 6 | 1 | LD Martínez G Oliveira | 7 | 6 | |||||||||||||||||||||
| TM Etcheverry C Ugo Carabelli | 2 | R Matos F Meligeni Alves | 5 | 1 | |||||||||||||||||||||||
MT Barrios Vera  C Gómez-Herrera | w/o | MT Barrios Vera C Gómez-Herrera | |||||||||||||||||||||||||
| 3 | S Galdós F Mena | w/o | |||||||||||||||||||||||||
| 3 | S Galdós F Mena | 4 | 4 | ||||||||||||||||||||||||
| G Andreozzi A Collarini | 2 | R Matos F Meligeni Alves | 6 | 6 | |||||||||||||||||||||||
| WC | Daniel Antonio Núñez Sebastián Santibáñez | w/o | WC | DA Núñez S Santibáñez | 5 | 2 | |||||||||||||||||||||
| 2 | R Matos F Meligeni Alves | 7 | 6 | ||||||||||||||||||||||||
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.
Guido Andreozzi and Guillermo Durán were the defending champions but chose not to defend their title.
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.
Ariel Behar and Gonzalo Escobar were the defending champions but only Escobar chose to defend his title, partnering Diego Hidalgo. Escobar lost in the first round to Íñigo Cervantes and Oriol Roca Batalla.
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.
Lloyd Glasspool and Matt Reid were the defending champions but chose not to defend their title.
Evan King and Julian Lenz were the defending champions but only King chose to defend his title, partnering Jan Zieliński. King lost in the first round to Franco Agamenone and Omar Giacalone.
Sander Arends and David Pel were the defending champions but chose not to defend their title.
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.
Luis David Martínez and Gonçalo Oliveira were the defending champions but lost in the semifinals to Evan King and Max Schnur.
Diego Hidalgo and Nicolás Jarry were the defending champions but only Hidalgo chose to defend his title, partnering Sergio Galdós. Hidalgo lost in the quarterfinals to Hans Hach Verdugo and Miguel Ángel Reyes-Varela.
Facundo Bagnis and Andrés Molteni were the defending champions but chose not to defend their title.
Sadio Doumbia and Fabien Reboul were the defending champions but chose not to defend their title.
Luis David Martínez and Felipe Meligeni Alves were the defending champions but chose to defend their title with different partners. Martínez partnered Fernando Romboli but lost in the semifinals to Nicolás Barrientos and Alejandro Gómez. Meligeni Alves partnered Rafael Matos but withdrew before the final due to a positive test for COVID-19.
Simone Bolelli and Máximo González were the defending champions but Bolelli chose not to participate. González was scheduled to partner Nicolás Jarry, but Jarry withdrew with a right elbow injury before their first round match.
Diego Hidalgo and Cristian Rodríguez were the defending champions but lost in the semifinals to Jesper de Jong and Bart Stevens.
Marcelo Arévalo and Miguel Ángel Reyes-Varela were the defending champions but only Reyes-Varela chose to defend his title, partnering Nicolás Barrientos. Reyes-Varela successfully defended his title, defeating Luis David Martínez and Felipe Meligeni Alves 7–6(13–11), 6–2 in the final.
Rafael Matos and Felipe Meligeni Alves were the defending champions but only Meligeni Alves chose to defend his title, partnering Matheus Pucinelli de Almeida. They withdrew before their first round match.