The current Slovenian terrestrial reference frame (D96-17) is a static frame based on GNSS technology. An additional transformation connecting it with the new realisation of ETRS89 accepted by EUREF (D17) gives the D96-17 a specific character. In order to ensure a high-quality national terrestrial reference frame, connection to the current realisation of ITRS is needed. This change is particularly important in the light of the intended transition to the semi-kinematic terrestrial reference frame, supported by a national geo-kinematic model. Transformations between the current national and international terrestrial reference frames are discussed in detail in the present paper. Processes, equations, and parameters of datum transformations are given in both directions (forward and inverse), step-by-step and direct ones, rigorous and simplified (approximate). Furthermore, an analysis of coordinate differences between current Slovenian and international terrestrial reference frames and an analysis of coordinate errors for various simplifications of transformation between both reference frames are given. This allows users to choose an optimal transformation solution to meet their requirements. The role and importance of transformations under consideration in the positioning procedures and the precise navigation are also addressed.