The 2021 L'Open 35 de Saint-Malo was a professional tennis tournament played on outdoor clay courts.

It was the twenty-sixth edition of the tournament and its first as part of the 2021 edition of the WTA 125K series.

It took place in Saint-Malo, France between 3 and 9 May 2021.

[1] The following players received wildcards into the singles main draw: The following players received entry from the qualifying draw: The following player received entry as a lucky loser: