| Doubles | |
|---|---|
| 2018 Kunal Patel San Francisco Open | |
| Champions |  Marcelo Arévalo  Roberto Maytín |
| Runners-up |  Luke Bambridge Joe Salisbury |
| Final score | 6–3, 6–7(5–7), [10–7] |
Matt Reid and John-Patrick Smith were the defending champions but chose not to defend their title.
Marcelo Arévalo and Roberto Maytín won the title after defeating Luke Bambridge and Joe Salisbury 6–3, 6–7(5–7), [10–7] in the final.
Ariel Behar / 
Máximo González (semifinals) Luke Bambridge / Joe Salisbury (final)
Jeevan Nedunchezhiyan / 
Christopher Rungkat (semifinals) Marcelo Arévalo / Roberto Maytín (champions)| First round | Quarterfinals | Semifinals | Final | ||||||||||||||||||||||||
| 1 | A Behar M González | 77 | 7 | ||||||||||||||||||||||||
 H Hach Verdugo  A Pavić | 62 | 5 | 1 | A Behar M González | 7 | 6 | |||||||||||||||||||||
| F Agamenone LD Martínez | 64 | 6 | [6] |  R Galloway M Krueger | 5 | 4 | |||||||||||||||||||||
| R Galloway M Krueger | 77 | 4 | [10] | 1 | A Behar M González | 1 | 63 | ||||||||||||||||||||
| 4 | M Arévalo R Maytín | 6 | 5 | [10] | 4 | M Arévalo R Maytín | 6 | 77 | |||||||||||||||||||
| WC | Nicholas Brunner Andre Dome | 3 | 7 | [5] | 4 | M Arévalo R Maytín | w/o | ||||||||||||||||||||
| LL | JC Aragone C Eubanks | 77 | 2 | [10] | LL | JC Aragone C Eubanks | |||||||||||||||||||||
| Q |  Í Cervantes JP Fruttero | 65 | 6 | [6] | 4 | M Arévalo R Maytín | 6 | 65 | [10] | ||||||||||||||||||
| WC | Alex Brenner N Chappell | 2 | 1 | 2 | L Bambridge J Salisbury | 3 | 77 | [7] | |||||||||||||||||||
D Novikov  G Oliveira | 6 | 6 | D Novikov G Oliveira | 6 | 1 | [9] | |||||||||||||||||||||
| WC |  A Göransson  F Lakat | 4 | 6 | [7] | 3 | J Nedunchezhiyan C Rungkat | 4 | 6 | [11] | ||||||||||||||||||
| 3 | J Nedunchezhiyan C Rungkat | 6 | 4 | [10] | 3 | J Nedunchezhiyan C Rungkat | 2 | 2 | |||||||||||||||||||
B Saraiva  S Verbeek | 6 | 6 | 2 | L Bambridge J Salisbury | 6 | 6 | |||||||||||||||||||||
 A Bublik M Mmoh | 0 | 2 | B Saraiva S Verbeek | 3 | 4 | ||||||||||||||||||||||
 R Gonzales H Reese | 7 | 63 | [8] | 2 | L Bambridge J Salisbury | 6 | 6 | ||||||||||||||||||||
| 2 | L Bambridge J Salisbury | 5 | 77 | [10] | |||||||||||||||||||||||
Andrés Molteni and Fernando Romboli were the defending champions, but both players chose not to participate.
Roberto Maytín and Hans Podlipnik-Castillo are the defending champions, but Maytín has partnered with Miguel Ángel Reyes-Varela and Podlipnik-Castillo has chosen not to participate. Roberto Maytín and Miguel Ángel Reyes-Varela are defeated by Ariel Behar and Giovanni Lapentti in the quarterfinals.
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.
Philip Bester and Peter Polansky were the defending champions but chose not to defend their title.
David O'Hare and Joe Salisbury were the defending champions but chose to defend their title with different partners. O'Hare partnered Luke Bambridge but lost in the final to Dominik Köpfer and Denis Kudla. Salisbury partnered Brydan Klein but lost in the semifinals to Bambridge and O'Hare.
Matt Reid and John-Patrick Smith were the defending champions but chose not to defend their title.
Austin Krajicek and Jackson Withrow were the defending champions but only Krajicek chose to defend his title, partnering Matt Reid. Krajicek withdrew before the tournament began due to injury.
Andre Begemann and Frederik Nielsen were the defending champions but chose not to defend their title.
This was the first edition of the tournament.
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.
André Göransson and Florian Lakat were the defending champions but lost in the quarterfinals to Gerard Granollers and Pedro Martínez.
Brydan Klein and Joe Salisbury were the defending champions but chose not to defend their title.
Denis Kudla and Danny Thomas were the defending champions but chose not to defend their title.
Robin Haase and Matwé Middelkoop were the defending champions, but chose to compete in Doha instead.
Evan King and Hunter Reese were the defending champions but only Reese chose to defend his title, partnering André Göransson. Reese lost in the first round to Treat Huey and Fabrice Martin.
Julian Ocleppo and Andrea Vavassori were the defending champions but chose to defend their title with different partners. Ocleppo partnered Andrea Pellegrino but lost in the first round to David Marrero and Roberto Maytín. Vavassori partnered Andrei Vasilevski but lost in the final to Tomislav Brkić and Ante Pavić.
Hans Hach Verdugo and Luke Saville were the defending champions but only Hach Verdugo chose to defend his title, partnering Dennis Novikov. Hach Verdugo lost in the first round to Alex Lawson and Jackson Withrow.
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.
Joe Salisbury and Neal Skupski were the defending champions, but Skupski chose to compete in Basel instead.
Bob and Mike Bryan were the two-time defending champions, but they retired in August 2020 so they did not defend their titles. Ariel Behar and Gonzalo Escobar won the title, defeating Christian and Ryan Harrison in the final, 6–7(5–7), 7–6(7–4), [10–4].