The 2025 Oeiras Indoors III was a professional tennis tournament played on hard courts.

It was the 7th edition of the tournament which was part of the 2025 ATP Challenger Tour.

It took place in Oeiras, Portugal from 21 to 26 January 2025.

The following players received wildcards into the singles main draw: The following players received entry into the singles main draw as alternates: The following players received entry from the qualifying draw: