The 2026 San Diego Open was a professional tennis tournament played on hardcourts. It was the second edition of the tournament as an ATP Challenger Tour event which was part of the 2026 ATP Challenger Tour. It was also the first edition of the tournament as part of the 2026 ITF Women's World Tennis Tour. It took place in San Diego, United States from 27 January to 1 February 2026.
The following players received wildcards into the singles main draw:
The following players received entry into the singles main draw as alternates:
The following players received entry from the qualifying draw:
The following players received wildcards into the singles main draw:
The following player received entry into the singles main draw using a special ranking:
The following players received entry from the qualifying draw: