Born in Girona, Catalonia, Joan Tomàs was an unsuccessful graduate from Espanyol's youth ranks, after which he moved to neighbours Lleida in the Segunda División B.

[2] During the 2008–09 campaign, also, he was one of the most important elements for the reserves as they eventually achieved a first-ever promotion to Segunda División.

[13] On 28 February, he scored with a scuffed shot to beat Olympiacos goalkeeper Yury Lodygin in a 1–0 away win that qualified for the semi-finals of the Greek Football Cup 4–3 on aggregate.

[15] Joan Tomàs moved countries again in late August 2019, with the 34-year-old agreeing to a deal at Liga 1 (Indonesia) club Persija Jakarta.

[16] He retired in 2023 after two seasons with amateurs CF Peralada in his native region, immediately being appointed their assistant manager.