- Source: 2018 Tiburon Challenger
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 September 24 and September 30, 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.