The 2021 Engie Open de Biarritz was the eighteenth edition of the Engie Open de Biarritz, a professional women's tennis tournament played on outdoor clay courts.

The 2021 edition of the tournament was part of the 2021 ITF Women's World Tennis Tour.

It took place in Biarritz, France from 12 to 18 July 2021.

[1] Viktoriya Tomova, the defending champion from the previous edition of the tournament, did not participate in the tournament in the 2021 edition.

The following players received wildcards into the singles main draw: The following player received entry using a protected ranking: The following player received entry using a junior exempt: The following players received entry from the qualifying draw: