The size effect of rock strength and properties is critical for the estimation of rock mass behaviour from laboratory-scale tests and has been studied extensively under both compression and indirect tension or Brazilian tests. However, the size effect has not been investigated in detail for rocks exhibiting well-controlled class-II or snap-back behaviour, especially under tension. This work examines the influence of specimen size on the tensile strength and fracture behaviour of South Australian Calca granite specimens in both conventional Brazilian tests and the Advanced Universal Snap-Back Indirect Tensile (AUSBIT) tests. Three specimen sizes of 31-, 54-, and 106.5-mm diameter discs were cored and prepared from rock blocks. By performing AUSBIT tests, the complete post-peak behaviour was obtained in all specimen sizes and was compared with Brazilian test results. Results showed that both the AUSBIT and Brazilian test specimens exhibit a decrease in strength with increasing size, indicating an evident size effect. In addition, acoustic emission (AE) data further reveal that the magnitudes of AE energy released by each crack during the failure stage decreased with size in Brazilian tests. On the contrary, the AE energy released by each crack in AUSBIT tests was found to increase with size. These results imply that the fracture behaviour of rocks is not only size-dependent but also influenced by the loading condition and subsequent failure mechanism. Furthermore, since AE correspond to micro-seismic signals in engineering applications, they could offer valuable insights into the fracturing state of rock masses. Finally, these findings indicate a potential optimum specimen size for the newly developed AUSBIT tests, along with size-related limitations to be considered for future improvements.