They include Brazilian trio of midfielder Kleyton Agostini from FC Santa Cruz and defenders Gabriel Yan and Rodrigo Mann.
Agostini (pictured), 27, signed for Santa Cruz in 2014, having previously been with fellow Brazilian sides Ferroviaria, Guarani de Camagua, Santo Angelo, Esportivo and Guaratingueta, where he began his career.
Yan, 21, joins the Hawks from Parana, while Mann, 23, signs from UA Barbarense, having previously been with Penapolense-SP and Parana.
The forth addition is French striker Wilfied Tagbo.
Tagbo, 26, has previously featured for PFC Velbazhd Kyustendil, FC Kaliakra in Bulgaria, Evry FC in France, Finn Harps in Ireland and most recently for Pars FC in Sweden.
The Hawks have also confirmed that goalkeeper Craig Ross has left the club.