2026 Open de Oeiras

Country	Player	Rank1	Seed
FRA	Valentin Royer	73	1
ITA	Mattia Bellucci	79	2
FRA	Luca Van Assche	94	3
ARG	Francisco Comesaña	99	4
USA	Mackenzie McDonald	126	5
SRB	Dušan Lajović	128	6
POR	Henrique Rocha	129	7
DEN	Elmer Møller	131	8

• ¹ Rankings are as of 6 April 2026.^[1]

The following players received wildcards into the singles main draw:

• Gastão Elias
• Frederico Ferreira Silva
• Tiago Pereira

The following player received entry into the singles main draw as a special exempt:

• Jurij Rodionov

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

• Marco Cecchinato
• Zdeněk Kolář
• Timofey Skatov

The following players received entry from the qualifying draw:

• Rémy Bertola
• Jonáš Forejtek
• Tom Gentzsch
• Felix Gill
• Pablo Llamas Ruiz
• Roman Safiullin

The following players received entry as lucky losers:

• Max Houkes
• Alejandro Moro Cañas

• Roman Safiullin def. Valentin Royer 6–1, 6–2.

• Sriram Balaji / Neil Oberleitner def. Nicolás Barrientos / Ariel Behar 6–7^(7–9), 6–4, [11–9].