Isaac Mabaya has been at Liverpool since six years of age. He is a right-sided midfielder but can also fit in at right-back. Mabaya was on the bench for Liverpool's first team in the FA Cup against Shrewsbury on 9 January 2022. He started well in Premier League 2 and the UEFA Youth League but was frustrated by injury in the second half of the season. He signed a new extended contract in May 2023 but the following season was plagued by injury and he made only five appearances in Premier League 2. Mabaya has represented England at under 19 level and is also qualified to play for Zimbabwe. Despite his injury problems his progress was rewarded with a first-team debut after he came on early after Joe Gomez' injury at Plymouth in the fourth round of the FA Cup on 9 February 2025. 

Mabaya spent the 2025/26 season on loan at Wigan Athletic in search of regular senior experience. However, his spell was cruelly disrupted almost immediately when he suffered a serious lower-limb injury in his first start for the League One club, in a League Cup tie against Notts County. The setback severely restricted his involvement, and he made only three appearances in all competitions during the campaign.