The 2021 Sardegna Open was a tennis tournament on the 2021 ATP Tour. It was played on outdoor clay courts in Cagliari, Sardinia, Italy. It was organised with a single-year licence in 2021, and was held at Tennis Club Cagliari from April 5 to 11, 2021.
The ATP 250 tournament debuted October 2020 as a response to the COVID-19 pandemic to increase earning opportunities for players. It returned to Sardegna in 2021 and opened the red-clay season in Europe.
<sub>*per team</sub>
The following players received wildcards into the main draw:
The following players received entry from the qualifying draw:
The following pairs received wildcards into the doubles main draw:
The following pair received entry using a protected ranking: