In 2013 Biel moved to Rayo Vallecano, returning to the youth setup. In July 2015, after finishing his formation and having appeared rarely for the B-team, he joined CD Llosetense also in the third division.[2]
On 21 May 2018 Biel renewed his contract until 2022, and was definitely promoted to the first team ahead of the 2018–19 season.[7] He scored his first professional goal on 12 November, netting his team's second in a 3–1 away defeat of Gimnàstic de Tarragona.
A regular starter under new manager Víctor Fernández, Biel scored a brace in a 3–3 draw at Cádiz CF on 8 April 2019. He finished the season with six goals in 21 appearances, as his side avoided relegation.
Copenhagen
On 1 August 2019, Danish Superliga side FC Copenhagen announced that they had agreed a fee with Zaragoza and that Biel would undergo a medical in Denmark with the intention of an immediate transfer.[8] Two days later, he signed a five-year contract with the club.[9]
On 27 February 2020, Biel scored in the final minutes to defeat Scottish champions Celtic and help the club advance to the round of 16 in the Europa League.[11][12]
On 8 August 2021, Biel scored the final goal in a 4–2 derby win against Brøndby.[13] On 7 September, Biel was named the Superliga Player of the Month for August 2021 after scoring five goals and providing two assists in five matches.[14] On 22 May 2022 with the club he won the Danish Superliga in the season 2021–22 been the first title in his career and he has been elected Copenhagen Player of the Season for the season 2021–22.[15]
Biel started the 2022–23 campaign in strong fashion, scoring four goals in four league games including a hat-trick against rivals Brøndby on 7 August 2022; the first hat-trick ever scored in a Copenhagen Derby.[16][17]
Olympiacos
Loan to Augsburg
On 1 February 2024, Biel joined German club Augsburg on loan for the rest of the season, with an option to buy.[18]
Loan to Charlotte FC
On 15 August 2024, Biel signed with Major League Soccer side Charlotte FC on loan until 31 December 2024.[19] Charlotte declined his contract option following their 2024 season.[20]
^"FCK enige med Real Zaragoza om Pep Biel" [FCK reach an agreement with Real Zaragoza over Pep Biel] (in Danish). FC Copenhagen. 1 August 2019. Retrieved 5 August 2019.