In this study, we report on the effect of Bioglass® structural transformations on its sintering behaviour. In a previous paper, we showed that while heating up to 1000°C, five successive transformations occur: glassy transition, phase separation, two crystallization processes and a second glassy transition. The sintering of the material exhibits two main shrinkage stages associated to the two glassy transitions at 550°C and 850°C. At 580°C, the glass-in-glass phase separation induces a decrease of the sintering rate immediately followed by the crystallisation of the major phase Na2CaSi2O6 between 600 and 700°C, from the surface to the bulk of the particles. A completed inhibition of sintering takes place followed by a minor shrinkage due to volume crystallization. A plateau is observed until the second glassy transition.