Mosta signed Mozambican defender Cláudio José Augusto Sumbane.
The twenty-five year old played for a number of clubs in his career, including Costa do Sol in Mozambique and Murteirense and Carregal do Sal in Portugal.
The club also secured the services of midfielder Terence Agius on loan from Birkirkara.
Mosta had earlier signed Santiago Martínez Perlaza, Pedro Luiz Soares Gusso, Ebrima Sohna, Christian Eric Chaney and Takanori Yokochi together with goalkeeper Nicky Vella.