The 2021 FC Caspiy season was Caspiy's second season back in the Kazakhstan Premier League, the highest tier of association football in Kazakhstan, since 2001. Caspiy would also take part in the Kazakhstan Cup.
On 26 February, Caspiy announced the signings of Taras Bondarenko, Chafik Tigroudja, Aslan Darabayev and Ruslan Mingazow.
On 1 March, Caspiy announced the signing of Aleksey Zaleski, David Karayev on loan from Ural Yekaterinburg and Talgat Kusyapov and Ramazan Karimov on loan from Astana.
On 5 March, Caspiy announced the signing of Maksim Gladchenko and Nikola CuckiÃÂ, whilst Niyaz Shugaev joined on loan from Shakhter Karagandy.
On 15 July, Stefan Bukorac joined Shakhter Karagandy on loan for the remainder of the season.
On 22 July, Arman Nusip left Caspiy after his contract was terminated by mutual consent.
On 30 July, Caspiy announced the loan signings of Jean-Ali Payruz from Shakhter Karagandy and Uladzimir Khvashchynski from Dinamo Minsk, both on contracts till the end of the season.
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|- |colspan="16"|Players away from Caspiy on loan:
|- |colspan="16"|Players who left Caspiy during the season: