| Doubles | |
|---|---|
| 2018 San Luis Open Challenger Tour | |
| Champions |  Marcelo Arévalo  Miguel Ángel Reyes-Varela |
| Runners-up |  Jay Clarke  Kevin Krawietz |
| Final score | 6–1, 6–4 |
Roberto Quiroz and Caio Zampieri were the defending champions but only Quiroz chose to defend his title, partnering Yannick Hanfmann. Quiroz lost in the quarterfinals to Jay Clarke and Kevin Krawietz.
Marcelo Arévalo and Miguel Ángel Reyes-Varela won the title after defeating Clarke and Krawietz 6–1, 6–4 in the final.
Austin Krajicek / Jackson Withrow (semifinals) Marcelo Arévalo / Miguel Ángel Reyes-Varela (champions)
Franco Agamenone / 
Sergio Galdós (quarterfinals) Evan King / Nathan Pasha (first round)| First round | Quarterfinals | Semifinals | Final | ||||||||||||||||||||||||
| 1 | A Krajicek J Withrow | 6 | 6 | ||||||||||||||||||||||||
| Alt |  P Sakamoto JP Sorgi | 4 | 4 | 1 | A Krajicek J Withrow | w/o | |||||||||||||||||||||
 P Krstin  D Muñoz de la Nava | 7 | 6 | P Krstin D Muñoz de la Nava | ||||||||||||||||||||||||
| A Collarini F Coria | 5 | 2 | 1 | A Krajicek J Withrow | 3 | 4 | |||||||||||||||||||||
| 4 | E King N Pasha | 64 | 77 | [6] | J Clarke K Krawietz | 6 | 6 | ||||||||||||||||||||
Y Hanfmann  R Quiroz | 77 | 63 | [10] | Y Hanfmann R Quiroz | 65 | 6 | [5] | ||||||||||||||||||||
| WC |  A Gómez T Hank | 4 | 1 | J Clarke K Krawietz | 77 | 3 | [10] | ||||||||||||||||||||
| J Clarke K Krawietz | 6 | 6 | J Clarke K Krawietz | 1 | 4 | ||||||||||||||||||||||
 B Arias F Zeballos | 4 | 77 | [10] | 2 | M Arévalo MÁ Reyes-Varela | 6 | 6 | ||||||||||||||||||||
| F Argüello F Bagnis | 6 | 65 | [4] | B Arias F Zeballos | 6 | 6 | |||||||||||||||||||||
| WC | E Gómez L Gómez | 1 | 4 | 3 | F Agamenone S Galdós | 3 | 4 | ||||||||||||||||||||
| 3 | F Agamenone S Galdós | 6 | 6 | B Arias F Zeballos | 4 | 4 | |||||||||||||||||||||
| WC | G López Villaseñor M Sánchez | 77 | 6 | 2 | M Arévalo MÁ Reyes-Varela | 6 | 6 | ||||||||||||||||||||
 LD Martínez  R Statham | 61 | 4 | WC | G López Villaseñor M Sánchez | 5 | 64 | |||||||||||||||||||||
| M Krueger A Sarkissian | 1 | 3 | 2 | M Arévalo MÁ Reyes-Varela | 7 | 77 | |||||||||||||||||||||
| 2 | M Arévalo MÁ Reyes-Varela | 6 | 6 | ||||||||||||||||||||||||
Daniele Bracciali and Potito Starace were the defending champions, but could not defend their title due to being banned from tennis for betting offences.
Alejandro Falla and Eduardo Struvay were the defending champions but chose not to defend their title.
Marcelo Demoliner and João Souza were the defending champions but chose not to defend their title.
Marcelo Arévalo and Sergio Galdós were the defending champions but chose to defend their title with different partners. Arévalo partnered Miguel Ángel Reyes-Varela and successfully defended his title. Galdós partnered Roberto Maytín but lost in the first round to Arévalo and Reyes-Varela.
Matt Reid and John-Patrick Smith were the defending champions but chose not to defend their title.
Evan King and Denis Kudla were the defending champions but only King chose to defend his title, partnering Christopher Eubanks. King successfully defended his title.
Ariel Behar and Fabiano de Paula were the defending champions but chose to defend their title with different partners. Behar partnered Attila Balázs but lost in the semifinals to Marcelo Arévalo and Miguel Ángel Reyes-Varela. De Paula partnered Sergio Galdós but lost in the first round to Hugo Dellien and Federico Zeballos.
Leander Paes and Adil Shamasdin were the defending champions but chose not to defend their title.
Ruan Roelofse and Christopher Rungkat were the defending champions but chose not to defend their title.
Leander Paes and Adil Shamasdin were the defending champions but chose not to defend their title.
Aisam-ul-Haq Qureshi and Rajeev Ram were the defending champions but Ram chose not to participate and Qureshi chose to compete in Båstad instead.
Juan Sebastián Cabal and Treat Huey were the defending champions, but Huey chose not to participate and Cabal chose to compete in Washington instead.
Christopher Eubanks and Evan King were the defending champions but only King chose to defend his title, partnering Nathan Pasha. King lost in the first round to Thanasi Kokkinakis and Matt Reid.
Juan Ignacio Londero and Luis David Martínez were the defending champions but only Londero chose to defend his title, partnering Tomás Lipovsek Puches. Londero lost in the semifinals to Leander Paes and Miguel Ángel Reyes-Varela.
Marcelo Arévalo and Miguel Ángel Reyes-Varela were the defending champions but chose not to defend their title.
Marcelo Arévalo and Miguel Ángel Reyes-Varela were the defending champions and successfully defended their title, defeating Ariel Behar and Roberto Quiroz 1–6, 6–4, [12–10] in the final.
Philipp Petzschner and Tim Pütz were the defending champions but only Pütz chose to defend his title, partnering Frederik Nielsen. Pütz lost in the final to Kevin Krawietz and Jürgen Melzer.
Marcelo Arévalo and Roberto Maytín were the defending champions but chose to defend their title with different partners. Arévalo partnered Miguel Ángel Reyes-Varela but lost in the first round to Ruben Gonzales and Ruan Roelofse. Maytín partnered Robert Galloway but lost in the first round to Nathan Pasha and Max Schnur.
Marcelo Arévalo and Miguel Ángel Reyes-Varela were the defending champions but chose not to defend their title.
Marcelo Arévalo and Miguel Ángel Reyes-Varela were the defending champions but chose not to defend their title.