2021 Open Castilla y León

Country	Player	Rank1	Seed
ESP	Feliciano López	89	1
FRA	Benjamin Bonzi	111	2
FRA	Grégoire Barrère	135	3
SUI	Marc-Andrea Hüsler	162	4
POR	Frederico Ferreira Silva	174	5
FRA	Quentin Halys	181	6
FRA	Mathias Bourgue	201	7
TUR	Altuğ Çelikbilek	203	8
TUR	Cem İlkel	209	9

• ¹ Rankings as of 19 July 2021.^[1]

The following players received wildcards into the singles main draw:

• Julio César Porras
• Alejandro Moro Cañas
• Nikolás Sánchez Izquierdo

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

• Adrian Andreev
• Johannes Härteis
• Filip Jianu

The following players received entry from the qualifying draw:

• Carlos Gimeno Valero
• Nicolas Moreno de Alboran
• Dalibor Svrčina
• Luca Vanni

• Benjamin Bonzi def. Tim van Rijthoven 7–6^(12–10), 3–6, 6–4.

• Robert Galloway / Alex Lawson def. JC Aragone / Nicolás Barrientos 7–6^(10–8), 6–4.