The 2025 Brest Open Groupe Vert was a professional tennis tournament played on hard courts. It was the tenth edition of the tournament which was part of the 2025 ATP Challenger Tour. It took place in Brest, France between 20 and 26 October 2025.
The following players received wildcards into the singles main draw:
The following player received entry into the singles main draw using a protected ranking:
The following player received entry into the singles main draw as a special exempt:
The following players received entry into the singles main draw as alternates:
The following players received entry from the qualifying draw:
The following player received entry as a lucky loser: