| Doubles | |
|---|---|
| 2018 Lisboa Belém Open | |
| Champions |  Marcelo Arévalo  Miguel Ángel Reyes-Varela |
| Runners-up |  Tomasz Bednarek  Hunter Reese |
| Final score | 6–3, 3–6, [10–1] |
Ruan Roelofse and Christopher Rungkat were the defending champions but chose not to defend their title.
Marcelo Arévalo and Miguel Ángel Reyes-Varela won the title after defeating Tomasz Bednarek and Hunter Reese 6–3, 3–6, [10–1] in the final.
Sander Arends / 
Adil Shamasdin (semifinals) Marcelo Arévalo / Miguel Ángel Reyes-Varela (champions)
Sergio Galdós / 
Fabrício Neis (quarterfinals)
Marin Draganja / Tomislav Draganja (semifinals)| First round | Quarterfinals | Semifinals | Final | ||||||||||||||||||||||||
| 1 | S Arends A Shamasdin | 2 | 77 | [10] | |||||||||||||||||||||||
 G Granollers J Munar | 6 | 62 | [8] | 1 | S Arends A Shamasdin | 79 | 6 | ||||||||||||||||||||
| E King N Pasha | 6 | 6 | E King N Pasha | 67 | 1 | ||||||||||||||||||||||
| WC |  Luís Faria Martim Leote Prata | 1 | 2 | 1 | S Arends A Shamasdin | 4 | 6 | [8] | |||||||||||||||||||
| 3 | S Galdós F Neis | 6 | 6 | T Bednarek H Reese | 6 | 2 | [10] | ||||||||||||||||||||
| WC | T Cação P Sousa | 4 | 2 | 3 | S Galdós F Neis | 4 | 1 | ||||||||||||||||||||
| T Bednarek H Reese | 6 | 6 | T Bednarek H Reese | 6 | 6 | ||||||||||||||||||||||
 L Broady S Clayton | 2 | 3 | T Bednarek H Reese | 3 | 6 | [1] | |||||||||||||||||||||
| WC | Francisco Dias Gonçalo Falcão | 5 | 6 | [10] | 2 | M Arévalo MÁ Reyes-Varela | 6 | 3 | [10] | ||||||||||||||||||
| N Lammons G Oliveira | 7 | 3 | [6] | WC | F Dias G Falcão | 0 | 2 | ||||||||||||||||||||
R Galloway  A Siljeström | 60 | 4 | 4 | M Draganja T Draganja | 6 | 6 | |||||||||||||||||||||
| 4 | M Draganja T Draganja | 77 | 6 | 4 | M Draganja T Draganja | 7 | 66 | [9] | |||||||||||||||||||
| T Robredo D Vega Hernández | 6 | 6 | 2 | M Arévalo MÁ Reyes-Varela | 5 | 78 | [11] | ||||||||||||||||||||
 A de Minaur M Reid | 3 | 3 | T Robredo D Vega Hernández | 6 | 1 | [6] | |||||||||||||||||||||
F Gil  S Robert | 1 | 4 | 2 | M Arévalo MÁ Reyes-Varela | 2 | 6 | [10] | ||||||||||||||||||||
| 2 | M Arévalo MÁ Reyes-Varela | 6 | 6 | ||||||||||||||||||||||||
Marin Draganja and Adrián Menéndez-Maceiras are the defending champions, but Marin Draganja chose not to compete. Adrián Menéndez-Maceiras played alongside Agustín Velotti.
Andrés Molteni and Fernando Romboli were the defending champions, but both players chose not to participate.
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 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.
The doubles event at the 2017 Milo Open Cali was won by Marcelo Arévalo and Miguel Ángel Reyes-Varela. Nicolás Jarry and Hans Podlipnik-Castillo were the defending champions but chose not to defend their title and did not participate in the 2017 event. Arévalo and Reyes-Varela won the title after defeating Sergio Galdós and Fabrício Neis 6–3, 6–4 in the final.
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.
This was the first edition of the tournament.
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.
Santiago González and Artem Sitak 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.
Marcelo Arévalo and Miguel Ángel Reyes-Varela were the defending champions but only Arévalo chose to defend his title, partnering Roberto Maytín. Arévalo lost in the first round to Luis David Martínez and David Pérez Sanz.
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 and successfully defended their title, defeating Ariel Behar and Roberto Quiroz 1–6, 6–4, [12–10] in the final.
Marcelo Arévalo and Miguel Ángel Reyes-Varela were the defending champions, but lost in the first round to Hans Hach Verdugo and Dennis Novikov.
Leander Paes and Miguel Ángel Reyes-Varela were the defending champions but only Reyes-Varela chose to defend his title, partnering Marcelo Arévalo. Reyes-Varela lost in the semifinals to Orlando Luz and Luis David Martínez.
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.