| 2025 Open de Oeiras II | |
|---|---|
| Date | 12–17 May |
| Edition | 13th |
| Surface | Clay |
| Location | Oeiras, Portugal |
| Champions | |
| Singles | |
 Cristian Garín | |
| Doubles | |
 Andreas Mies /  David Vega Hernández | |
The 2025 Open de Oeiras II was a professional tennis tournament played on clay courts. It was the 13th edition of the tournament which was part of the 2025 ATP Challenger Tour. It took place in Oeiras, Portugal between 12 and 17 May 2025.
| Country | Player | Rank1 | Seed |
|---|---|---|---|
 BRA | Thiago Monteiro | 106 | 1 |
 POR | |||
 USA | Christopher Eubanks | 110 | 3 |
 DEN | |||
| USA | Tristan Boyer | 122 | 5 |
| BRA | Felipe Meligeni Alves | 123 | 6 |
 ARG | Thiago Agustín Tirante | 133 | 7 |
| ARG | Román Andrés Burruchaga | 135 | 8 |
The following players received wildcards into the singles main draw:
Pedro Araújo Gastão Elias Tiago PereiraThe following player received entry into the singles main draw using a protected ranking:
The following players received entry into the singles main draw as alternates:
The following players received entry from the qualifying draw:
The following players received entry as lucky losers:
Cristian Garín def. Mitchell Krueger 7–6(7–3), 4–6, 6–2. Andreas Mies / David Vega Hernández def. Marcelo Demoliner / 
David Pichler 6–4, 6–4.
