The 2018 Kunal Patel San Francisco Open was a professional tennis tournament played on indoor hard courts. It was the second edition of the tournament and was a part of the 2018 ATP Challenger Tour. It took place in San Francisco, United States from February 5–11, 2018.

Country	Player	Rank1	Seed
KAZ	Alexander Bublik	131	1
USA	Mackenzie McDonald	158	2
USA	Michael Mmoh	164	3
USA	Denis Kudla	167	4
USA	Bradley Klahn	175	5
USA	Noah Rubin	180	6
CAN	Filip Peliwo	186	7
CAN	Brayden Schnur	192	8

• ¹ Rankings are as of January 29, 2018.

The following players received wildcards into the singles main draw:

• Christopher Eubanks
• Christian Garín
• Florian Lakat
• Danny Thomas

The following players received entry from the qualifying draw:

• JC Aragone
• Máximo González
• Jared Hiltzik
• Karue Sell

• Jason Jung def. Dominik Köpfer 6–4, 2–6, 7–6^(7–5).

• Marcelo Arévalo / Roberto Maytín def. Luke Bambridge / Joe Salisbury 6–3, 6–7^(5–7), [10–7].

• Official website Archived 2017-02-04 at the Wayback Machine