The 2018 Tiburon Challenger was a professional tennis tournament played on outdoor hard courts. It was the twelfth edition of the tournament which was part of the 2018 ATP Challenger Tour. It took place in Tiburon, United States between 24 and 30 September 2018.
Singles main draw entrants
Seeds
1 Rankings are as of September 17, 2018.
Other entrants
The following players received wildcards into the singles main draw: JC Aragone Tom Fawcett Brandon Holt Tommy Paul
The following player received entry into the singles main draw as a special exempt: Mikael Torpegaard
The following player received entry into the singles main draw as an alternate: James Duckworth
The following players received entry from the qualifying draw: Steven Diez Cem İlkel Roberto Ortega Olmedo Alexander Sarkissian
Champions
Singles
Michael Mmoh def. Marcel Granollers 6–3, 7–5.
Doubles
Hans Hach Verdugo / Luke Saville def. Gerard Granollers / Pedro Martínez 6–3, 6–2.