Rice is a globally important staple crop valued not only for sustenance but also for its potential health benefits, yet Philippine pigmented rice varieties remain underexplored. This study evaluated the phytochemical composition and antioxidant activity of five Philippine rice varieties cultivated in the Cordillera region—white rice, brown rice, red rice, purple rice, and black rice—using two extraction techniques: maceration and ultrasound-assisted extraction (UAE). Both methods used 80% methanol as the solvent (1:10 w/v); maceration (48 h, room temperature) and UAE (30 min, room temperature). Total phenolic content (TPC), total flavonoid content (TFC), and total anthocyanin content (TAC) were quantified using the Folin–Ciocalteu, aluminum chloride colorimetric, and pH differential methods, respectively. Antioxidant activity was assessed via the DPPH assay and expressed as EC₅₀ values. Pigmented rice varieties exhibited higher levels of phenolics and anthocyanins, along with stronger antioxidant activity, compared to non-pigmented rice. Among all samples, red rice extracted via UAE showed the highest TPC (731.25 ± 0.02 mg GAE/100 g), highest TFC (9.69 ± 1.56 mg QE/100 g), and one of the highest TAC values (183.69 ± 16.70 mg C3G/100 g), with the lowest EC₅₀ value (52.49 ± 0.23 μg/mL), indicating strong antioxidant potential. UAE outperformed maceration in enhancing phytochemical yield and antioxidant activity, likely due to better cell disruption and compound release. Pearson correlation analysis revealed a strong positive correlation between TPC and TAC (r = +0.745), and significant negative correlations between antioxidant EC₅₀ and both TPC (r = –0.847) and TAC (r = –0.804). These results suggest that phenolic and anthocyanin contents strongly contribute to antioxidant capacity and support the potential of pigmented Philippine rice as a functional food and antioxidant source.