| Score: | 7–6(7–4), 1–6, [12–10] |
| Type: | singles doubles |
See main article: article and 2018 Challenger ATP Cachantún Cup.
Marcelo Tomás Barrios Vera and Nicolás Jarry were the defending champions but only Barrios Vera chose to defend his title, partnering José Hernández-Fernández. Barrios Vera lost in the semifinals to Romain Arneodo and Jonathan Eysseric.
Arneodo and Eysseric won the title after defeating Guido Andreozzi and Guillermo Durán 7–6(7–4), 1–6, [12–10] in the final.[1]