| Date: | 5–10 June |
| Edition: | 13th |
| Category: | WTA 125K series |
| Location: | Bol, Croatia |
| Venue: | Bluesun Tennis Center Zlatni rat |
| Prize Money: | $125,000 |
| Champs: | Tamara Zidanšek |
| Champd: |  Mariana Duque Mariño /  Wang Yafan |
The 2018 Bol Open was a professional tennis tournament played on outdoor clay courts. It was the thirteenth edition of the tournament and part of the 2018 WTA 125K series. It took place in Bol, Croatia, on 5–10 June 2018.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 Ukraine | Kateryna Kozlova | 67 | 1 | |
 Poland | Magda Linette | 68 | 2 | |
 Australia | Ajla Tomljanović | 69 | 3 | |
 Italy | Sara Errani | 75 | 4 | |
 Slovakia | Anna Karolína Schmiedlová | 77 | 5 | |
| China | Wang Yafan | 82 | 6 | |
| Viktorija Golubic | 110 | 7 | ||
| Colombia | Mariana Duque Mariño | 112 | 8 |
The following players received a wildcard into the singles main draw:
Jennifer Brady → replaced by 
Elena-Gabriela Ruse Jana Čepelová → replaced by 
Tereza Martincová Kristína Kučová
Johanna Larsson → replaced by 
Sílvia Soler Espinosa Bernarda Pera → replaced by Alexandra Cadanțu Rebecca Peterson → replaced by Viktoriya Tomova
Yulia Putintseva → replaced by Michaela Hončová
Sofya Zhuk| Country | Player | Country | Player | Rank1 | Seed | |
|---|---|---|---|---|---|---|
| Xenia Knoll | Czech Republic | Renata Voráčová | 102 | 1 | ||
| United States | Kaitlyn Christian | United States | Sabrina Santamaria | 165 | 2 | |
| Darija Jurak | Sweden | Cornelia Lister | 170 | 3 | ||
| Colombia | Mariana Duque-Mariño | China | Wang Yafan | 208 | 4 |
The following team received wildcard into the doubles draw:
See main article: 2018 Bol Open – Singles.
Magda Linette 6–1, 6–3See main article: 2018 Bol Open – Doubles.
Mariana Duque Mariño / Wang Yafan def. Sílvia Soler Espinosa / Barbora Štefková 6–3, 7–5