The optical properties of rare-earth-doped Ga2O3 powders, films, and single crystals have been widely explored for phosphors, deep-UV optoelectronics, and scintillator applications, making it attractive to fabricate Ga2O3 transparent ceramics. However, there are few studies on Ga2O3 ceramics and even fewer on transparent ceramics due to the serious reduction reaction and monoclinic structure of Ga2O3. In this study, we first prepared different rare earth (RE) elements (Er-, Dy-, Tb-) doped Ga2O3 powders via the co-precipitation method and sintered them into transparent ceramics by spark plasma sintering (SPS). It is demonstrated that the unique orientation and dense microstructure contributed to the good transparency of the non-cubic Ga2O3 transparent ceramics. Additionally, the transmittance, luminescence performance, and fluorescence decay time of the doped ceramics were studied in detail, indicating the effective optical activity of the rare earth elements in Ga2O3 ceramics.