Sonny Cox, a former pupil of Exmouth Community College, signed a scholarship contract with Exeter City in July 2021 followed by a professional deal in November 2021. 

As an under-16 player Sonny had featured prominently with Exeter City under-18s in both the Youth Alliance and FA Youth Cup as well as sitting on the bench for first-team EFL Trophy games. After reportedly having a trial with Manchester United, he joined the Grecians as a scholar/trainee on leaving school in 2021. Making his first-team debut as a substitute against Cheltenham Town in the EFL Trophy on 5 October 2021, Sonny later played against Bristol Rovers in the same competition. Shortly afterwards, in November 2021, he upgraded his existing agreement with the club by signing a full professional deal prior to spending the second-half of the season on loan with Weston-super-Mare who he helped reach the Southern League play-offs.

Sonny’s second full-season followed a similar path. He made his league debut as a second-half substitute against Cheltenham Town on 20 August 2022 and his first start in professional football against Newport County in the EFL Trophy on 30 August 2022. His first league goal - as a substitute in stoppage time - came against Oxford United on 15 October 2022 before later loan appearances for Bath City between December 2022 and April 2023. 

After participating on a more regular basis in City's first-team at the start of 2023/24, Sonny was lent to Yeovil Town between October and December 2023 before returning to St James' Park to score the only goal when City ended a long winless run with a Boxing Day victory over Wycombe Wanderers. He also scored in the home win over Carlisle United and the away win at Bristol Rovers prior to adding a memorable quickfire double early in the second half against Bolton Wanderers.

Agreeing a contract extension to the end of the 2025/26 season, Sonny clocked up 37 appearances in all competitions during 2023/24 - 23 starts and 14 as a substitute - and, five months short of his 20th birthday, had made in excess of fifty first-team appearances when he was named the Disabled Supporters' Association 'most improved player for the season'. But, heading into the 2024/25 season, he had to wait until March before adding to his tally of league goals with a strike against Northampton Town in what proved to be a challenging season as he appeared in just half of the club's league games with the majority of his outings coming from the substitute's bench. 

2025/26 proved to be a similar story for Sonny as he started just ten league games - scoring once against Blackpool early in the season - and, in a campaign that finished with City's relegation to League Two, he failed to make a first-team appearance beyond mid-March.

Exeter City to end of 2025/26

League 91; Cups 18 (109)