Metal oxide (MO) semiconductors are widely used in electronic devices due to their high optical transmittance and promising electrical performance. This work describes the advancement toward an eco-friendly, streamlined method for preparing thin-film transistors (TFTs) via a pure water-solution blade-coating process with focus on a low thermal budget. Low temperature and rapid annealing of triple-coated indium oxide thin-film transistors (3C-TFTs) and indium oxide/zinc oxide/indium oxide thin-film transistors (IZI-TFTs) on a 300 nm SiO2 gate dielectric at 300 °C for only 60 s yields devices with an average field effect mobility of 10.7 and 13.8 cm2 V−1 s−1, respectively. The devices show an excellent on/off ratio (>106), and a threshold voltage close to 0 V when measured in air. Flexible MO-TFTs on polyimide substrates with AlOx dielectrics fabricated by rapid annealing treatment can achieve a remarkable mobility of over 10 cm2 V−1 s−1 at low operating voltage. When using a longer post-coating annealing period of 20 min, high-performance 3C-TFTs (over 18 cm2 V−1 s−1) and IZI-TFTs (over 38 cm2 V−1 s−1) using MO semiconductor layers annealed at 300 °C are achieved.