| Doubles | |
|---|---|
| 2021 Murcia Open | |
| Champions |  Raúl Brancaccio  Flavio Cobolli |
| Runners-up | Alberto Barroso Campos Roberto Carballés Baena |
| Score | 6–3, 7–6(7–4) |
Marcus Daniell and David Marrero were the defending champions [1] but chose not to defend their title.
Raúl Brancaccio and Flavio Cobolli won the title after defeating Alberto Barroso Campos and Roberto Carballés Baena 6–3, 7–6(7–4) in the final.
Sriram Balaji / Ramkumar Ramanathan (semifinals)
Jesper de Jong / Bart Stevens (quarterfinals)
Vladyslav Manafov / 
Piotr Matuszewski (quarterfinals) Alberto Barroso Campos / Roberto Carballés Baena (final)| First round | Quarterfinals | Semifinals | Final | ||||||||||||||||||||||||
| 1 | S Balaji R Ramanathan | 77 | 6 | ||||||||||||||||||||||||
| Davide Galoppini F Passaro | 79 | 5 | [10] | D Galoppini F Passaro | 65 | 3 | |||||||||||||||||||||
| WC | Pablo Martínez Gómez D Rincón | 67 | 7 | [4] | 1 | S Balaji R Ramanathan | 5 | 66 | |||||||||||||||||||
| 4 | A Barroso Campos R Carballés Baena | 7 | 78 | ||||||||||||||||||||||||
| 4 | A Barroso Campos R Carballés Baena | 6 | 77 | ||||||||||||||||||||||||
| R Ortega Olmedo C Sánchez Jover | 5 | 1 |  C Denolly M Martineau | 1 | 62 | ||||||||||||||||||||||
| C Denolly M Martineau | 7 | 6 | 4 | A Barroso Campos R Carballés Baena | 3 | 64 | |||||||||||||||||||||
| R Brancaccio F Cobolli | 6 | 78 | R Brancaccio F Cobolli | 6 | 77 | ||||||||||||||||||||||
| PR | A Chandrasekar Manish Sureshkumar | 2 | 66 | R Brancaccio F Cobolli | 6 | 6 | |||||||||||||||||||||
| 3 | V Manafov P Matuszewski | 4 | 4 | ||||||||||||||||||||||||
| R Brancaccio F Cobolli | 77 | 7 | |||||||||||||||||||||||||
 A Collarini Mariano Kestelboim | 5 | 4 | PR |  J De Loore J Vanneste | 64 | 5 | |||||||||||||||||||||
| PR | J De Loore Jeroen Vanneste | 7 | 6 | PR | J De Loore J Vanneste | 6 | 4 | [10] | |||||||||||||||||||
| 2 | J de Jong B Stevens | 4 | 6 | [7] | |||||||||||||||||||||||
Stanislas Wawrinka was the defending champion, but withdrew before the event started.
Carlos Berlocq won the title, defeating Tomáš Berdych in the final, 0–6, 7–5, 6–1.
Pablo Cuevas was the defending champion and successfully defended his title, defeating Pablo Carreño Busta in the final, 7–6(7–4), 6–3.
Roberto Carballés Baena was the defending champion but lost in the quarterfinals to Uladzimir Ignatik.
Víctor Estrella Burgos was the two-time defending champion and successfully defended his title, defeating Paolo Lorenzi in the final, 6–7(2–7), 7–5, 7–6(8–6).
Pablo Cuevas was the two-time defending champion and successfully defended his title, defeating Albert Ramos Viñolas in the final, 6–7(3–7), 6–4, 6–4.
João Souza was the defending champion but chose not to defend his title.
Leonardo Mayer was the defending champion but chose not to defend his title.
Víctor Estrella Burgos was the three-time defending champion and the tournament's only champion to date, but lost in the second round to Gerald Melzer.
Dominic Thiem was the defending champion, but lost in the quarterfinals to Fernando Verdasco.
Marin Čilić was the defending champion, but lost in the second round to Diego Schwartzman.
Juan Pablo Varillas was the defending champion but chose not to participate.
Roberto Carballés Baena and Alejandro Davidovich Fokina were the defending champions, but Davidovich Fokina chose to participate in Marseille instead. Carballés Baena partnered Federico Coria but lost in the first round to Raven Klaasen and Ben McLachlan.
Albert Ramos Viñolas defeated Cameron Norrie in the final, 4–6, 6–3, 7–6(7–3) to win the singles tennis title at the 2021 Estoril Open. It marked his third career ATP Tour singles title, all of which have been on clay. Norrie was aiming to win his first ATP Tour title in his second final.
Alejandro Davidovich Fokina was the defending champion but chose not to defend his title.
Andrey Rublev was the defending champion, but chose to compete in St. Petersburg instead.
Carlos Gimeno Valero was the defending champion but lost in the second round to Salvatore Caruso.
Pablo Cuevas was the defending champion but chose not to participate.
Pedro Martínez was the defending champion but lost in the first round to Kimmer Coppejans.
David Vega Hernández and Mark Vervoort were the defending champions but chose not to defend their title.
Román Andrés Burruchaga and Facundo Díaz Acosta were the defending champions but chose not to defend their title.