Dense yttria ceramics were prepared by Spark Plasma Sintering of a nanopowder synthesized using a PEG assisted combustion method. Densification occurs between 800 °C and 900 °C without any additive. This corresponds to one of the lowest sintering temperature found in the literature for Y2O3. Because of a significant release of organic species, the Y2O3 precursors obtained by this synthesis route contains macropores that have a negative impact on the final microstructure. We show that the emergence of these macropores can be minimized by decreasing the annealing temperature used for the precursor powder (in a temperature range of 300–650 °C) as opposed to the usual 800 °C. Finally, a precursor annealed at 650 °C allows us to obtain fully dense ceramics, with a very fine and homogeneous microstructure (and a grain size around 300 nm). Vickers microhardness and fracture toughness were measured and discussed in relation to the microstructure of the ceramics.