2021 Croatia Open Umag

The 2021 Croatia Open (also known as the Plava Laguna Croatia Open Umag for sponsorship reasons) is a men's tennis tournament played on outdoor clay courts. It is the 31st edition of the Croatia Open, and part of the 250 Series of the 2021 ATP Tour. It take place at the International Tennis Center in Umag, Croatia, from 19 through 25 July 2021.

Singles

 * 🇪🇸 Carlos Alcaraz def. 🇫🇷 Richard Gasquet, 6–2, 6–2

Doubles

 * 🇧🇷 Fernando Romboli / 🇪🇸 David Vega Hernández def. 🇧🇦 Tomislav Brkić / 🇷🇸 Nikola Ćaćić, 6–3, 7–5

Prize money

 * per team

Seeds

 * 1 Rankings are as of 12 July 2021.

Other entrants
The following players received wildcards into the main draw:
 * Duje Ajduković
 * Holger Rune
 * Nino Serdarušić

The following players received entry from the qualifying draw:
 * 🇩🇪 Daniel Altmaier
 * 🇦🇷 Andrea Collarini
 * 🇮🇹 Alessandro Giannessi
 * 🇸🇰 Filip Horanský

The following player received entry as a lucky loser:
 * 🇦🇷 Renzo Olivo

Withdrawals

 * Before the tournament
 * 🇮🇹 Salvatore Caruso → replaced by 🇦🇷 Renzo Olivo
 * 🇯🇵 Taro Daniel → replaced by 🇸🇰 Andrej Martin
 * 🇮🇹 Lorenzo Musetti → replaced by 🇪🇸 Carlos Taberner

Seeds

 * 1 Rankings are as of 12 July 2021.

Other entrants
The following pairs received wildcards into the doubles main draw:
 * Duje Ajduković / Frane Ninčević
 * Admir Kalender / Mili Poljičak

Withdrawals

 * Before the tournament
 * 🇮🇹 Simone Bolelli / 🇦🇷 Máximo González → replaced by 🇧🇦 Damir Džumhur / Antonio Šančić