Mallorca Born in
Porreres,
Majorca,
Balearic Islands, Sastre graduated from local
RCD Mallorca's youth system, and made his senior debuts with
the reserves in the
2014–15 campaign, in
Segunda División B. On 10 September 2015, he made his first team debut, starting in a 2–0 home loss against
Huesca, for
the season's
Copa del Rey. Ahead of the
2017–18 season, Sastre was definitely promoted to the first team by new manager
Vicente Moreno, with the side now in the third level. He scored his first senior goal on 10 December 2017, netting the equalizer in a 1–1 away draw against
CF Badalona. On 30 December 2017, Sastre renewed his contract with the
Bermellones until 2020. He subsequently featured regularly as the club achieved two consecutive promotions, and further extended his deal until 2023 on 22 July 2019. Sastre made his
La Liga debut on 17 August 2019, starting in a 2–1 home win over
SD Eibar. He shared the starting spot with
Fran Gámez during
the season, as Mallorca suffered relegation. Sastre scored his first professional goal on 3 January 2021, netting his team's second in a 2–2
Segunda División away draw against
Real Oviedo. After Mallorca signed
Pablo Maffeo from
VfB Stuttgart, Joan was no more a first team player so in the winter transfer season they decided to loan him to
PAOK on a six-month contract with a buy option for the following season.
Loan to PAOK On 12 January 2022,
PAOK officially announced the acquisition of Sastre from Mallorca on loan for the remainder of the season, with an option to buy. Sastre scored his first goal against
Volos on his debut on 22 January 2022.
PAOK In summer 2023, PAOK enabled the permanent buy-out option from Mallorca for €400,000. ==Career statistics==