In the present work, the reactions of cyclophosphazenes with adamantane derivatives have been investigated. The geminal-bis- (3) and geminal-tetrakis- (4) compounds have been synthesized from the reaction of hexachloro-cyclotriphosphazatriene with 1-adamantanethiol. 2-(1′-Adamantylamino)-2,4,4,6,6-pentachlorocyclotriphosphazatriene (5) has been obtained from the reaction of hexachloro-cyclotriphosphazatriene with 1-adamantylamine. Furthermore, mono- (6) and non-geminal bis-substituted 1-adamantylamino cyclotetraphosphazene compounds 7 (2-trans-6) and 8 (2-cis-4) have been isolated from the reaction of octachlorocyclotetraphosphazatetraene with 1-adamantylamine. All compounds have been fully characterized by elemental analysis, mass, 1H and 31P NMR spectroscopies. Molecular and crystal structures of 3 and 5–7 have been determined by X-ray crystallography. Compounds 3 and 4 are reported as the first examples for adamantylthio derivatives of cyclophosphazene in the literature. Compounds 5–8 have been also reported for the first time.