Adele Thomas was born and raised in Port Talbot in South Wales. She is an Honorary Fellow of Fitzwilliam College, Cambridge University and of Gower College in Swansea. Adele is also an alumnus of the Regional Theatre Young Directors' Scheme and the National Theatre Studio Directors' Course. In 2025, she jointly took up the post of Co-General Director and CEO of Welsh National Opera with Sarah Crabtree.

As a director, her opera work includes Ballo in Maschera at Edinburgh International Festival and Opernhaus Zürich, Tannhäuser (Theater Magdeburg), Rigoletto (Welsh National Opera), Semele (Glyndebourne) Il Trovatore (Opernhaus Zürich and Royal Opera House), In the Realms of Sorrow (London Handel Festival/ Stone Nest), Bajazet (Irish National Opera and Royal Opera House), Il Trovatore (Opernhaus Zürich and Royal Opera House), Apollo e Dafne, Berenice (Royal Opera House), Cosi Fan Tutte (Northern Ireland Opera). Both Bajazet and Berenice were nominated for the Olivier Award for Best New Opera Production. In 2022, she was nominated for an International Opera Award in the director category.

She has previously worked for National Theatre Wales on their renowned production The Passion, before working on the London stage as a Theatre Director. Her London debut was The Knight of the Golden Pestle in the opening season of the Globe's Sam Wanamaker Playhouse. Theatre credits include: The Memory of Water (Nottingham Playhouse), The Weir (ETT), Macbeth (Tobacco Factory) Eyam, The Orestei, The Knight of the Burning Pestle and Thomas Tallis, (Shakespeare's Globe); The Golden Hours: as part of Unusual Unions (Royal Court); The Bloody Ballad, The Forsythe Sisters, (Gagglebabble); The Passion and The Passion: One Year On (as Project Associate for National Theatre Wales); Under Milk Wood(Royal & Derngate)

Adele was one of the founding members of Freelancers Make Theatre Work; a group advocating for the voice of freelance theatre workers during COVID-19.