| 2018 Croatia Open Umag | |
|---|---|
| Date | 15 – 22 July |
| Edition | 29th |
| Category | ATP World Tour 250 |
| Draw | 28S/16D |
| Prize money | €482,060 |
| Surface | Clay |
| Location | Umag, Croatia |
| Champions | |
| Singles | |
 Marco Cecchinato | |
| Doubles | |
 Robin Haase / Matwé Middelkoop | |
The 2018 Croatia Open Umag (also known as the Plava Laguna Croatia Open Umag for sponsorship reasons) was a men's tennis tournament played on outdoor clay courts. It was the 29th edition of the Croatia Open, and part of the ATP World Tour 250 Series of the 2018 ATP World Tour. It took place at the International Tennis Center in Umag, Croatia, from 15 July through 22 July 2018.