[12] In March 2021, Kent announced the signing of West Indian international fast bowler Miguel Cummins for the first eight matches of the County Championship.

[13][14] Zimbabwean born batsman Tawanda Muyeye, who qualifies as a domestic player having been educated at Eastbourne College, signed his first professional contract with the club on 31 March 2021.

[17] On 8 June, however, it was confirmed that Amir would be unable to join up with the squad due to rescheduling of the Pakistan Super League and COVID-19-related travel restrictions.

[25] Kent called up a number of second team players and signed other homegrown players to join the remainder of the senior squad for a Championship game against Sussex; Joe Gordon, Harry Houillon, Dan Lincoln, Jas Singh and Bailey Wightman all made their first-class debuts, and Harry Finch played his first game for Kent against his former team.

[26][27] Kent signed three Scotland international players – Calum MacLeod, George Munsey and Safyaan Sharif – to strengthen the squad for the last two matches of the T20 Blast group stage.

[28] Elliot Hooper also made his Kent debut in the T20 Blast fixture against Middlesex, having previously played a single first-class game for Sussex.

[3] The following second team players and short-term signings also featured in matches, but were not members of the long-term squad during the season: Harry Houillon, Calum MacLeod, Safyaan Sharif, Jas Singh, Elliot Hooper and Bailey Wightman.

[3] Leaning was selected by the Trent Rockets as short-term cover for Steven Mullaney, meaning that he would miss games against Sussex and Essex, with Robinson taking over as captain.