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Polyhydroxyalkanoates (PHA) have received attention owing to their biodegradability and biocompatibility, with studies exploring PHA-producing bacterial strains. As vegetable oil provides carbon and monomer precursors for poly(3-hydroxybutyrate-<i>co</i>-3-hydroxyhexanoate) (P(3HB-<i>co</i>-3HHx)), oil-utilizing strains may facilitate PHA production. Herein, <i>Cupriavidus necator</i> BM3-1, which produces 11.1 g/L of PHB with 5% vegetable oil, was selected among various novel <i>Cupriavidus necator</i> strains. This strain exhibited higher preference for vegetable oils over sugars, with soybean oil and tryptone determined to be optimal sources for PHA production. BM3-1 produced 33.9 g/L of exopolysaccharides (EPS), which was three-fold higher than the amount produced by H16 (10.1 g/L). EPS exhibited 59.7% of emulsification activity (EI24), higher than that of SDS and of EPS from H16 with soybean oil. To evaluate P(3HB-<i>co</i>-3HHx) production from soybean oil, BM3-1 was engineered with P(3HB-<i>co</i>-3HHx) biosynthetic genes (<i>phaC_Ra</i>, <i>phaA_Re</i>, and <i>phaJ_Pa</i>). BM3-1/pPhaCJ produced 3.5 mol% of 3HHx and 37.1 g/L PHA. BM3-1/pCB81 (phaCAJ) produced 32.8 g/L PHA, including 5.9 mol% 3HHx. Physical and thermal analyses revealed that P(3HB-<i>co</i>-5.9 mol% 3HHx) was better than PHB. Collectively, we identified a novel strain with high vegetable oil utilization capacity for the production of EPS, with the option to engineer the strain for P(3HB-<i>co</i>-3HHx).