2018 Croatia Open Umag

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.

Seeds

 * 1 Rankings are as of July 2, 2018

Other entrants
The following players received wildcards into the singles main draw:
 * 🇨🇦 Félix Auger-Aliassime
 * Nino Serdarušić
 * Franko Škugor

The following players received entry from the qualifying draw:
 * 🇧🇷 Rogério Dutra Silva
 * 🇸🇰 Martin Kližan
 * 🇮🇹 Stefano Travaglia
 * 🇦🇷 Marco Trungelliti

The following player received entry as a lucky loser:
 * 🇸🇰 Andrej Martin

Withdrawals

 * Before the tournament
 * 🇬🇧 Kyle Edmund → replaced by 🇸🇰 Andrej Martin
 * 🇪🇸 Guillermo García López → replaced by 🇷🇸 Laslo Đere
 * 🇷🇸 Filip Krajinović → replaced by 🇯🇵 Taro Daniel
 * 🇮🇹 Andreas Seppi → replaced by 🇦🇷 Guido Pella

Seeds

 * Rankings are as of July 2, 2018

Other entrants
The following pairs received wildcards into the doubles main draw:
 * Marin Draganja / Tomislav Draganja
 * Ivan Sabanov / Matej Sabanov

The following pair received entry as alternates:
 * Nicolás Jarry / 🇪🇨 Roberto Quiroz

Withdrawals

 * Before the tournament
 * Ariel Behar

Men's singles

 * 🇮🇹 Marco Cecchinato def. 🇦🇷 Guido Pella, 6–2, 7–6(7–4)

Men's doubles

 * Robin Haase / Matwé Middelkoop def. 🇨🇿 Roman Jebavý / 🇨🇿 Jiří Veselý, 6–4, 6–4