See main article: article and 2018 St. Petersburg Ladies' Trophy.
Kristina Mladenovic was the defending champion, but lost in the final to unseeded Petra Kvitová, 1–6, 2–6. As a result, Kvitová became the first left-handed player to win a singles title in Russia. She was also the first wildcard to win the event.
The top four seeds received a bye into the second round.