We investigated the ferroelectric, piezoelectric, and domain wall current properties affected by the distribution of a-oriented domains and c-oriented domains in flexible SrBi2Ta2O9 (SBT) thin films on flexible Pt/mica substrates. On the flexible Pt/mica substrates, the SBT thin films with a mixed crystallinity of a-oriented and c-oriented crystallinities exhibited the domain structures mixed with a-oriented domains and c-oriented domains. The SBT thin films with excellent a-oriented crystallinity showed improved ferroelectric and piezoelectric properties due to the polar axis perpendicular to the c-axis. In particular, 90o domain walls composed of a-domain and c-domain have larger domain wall currents than 180o domain walls composed of c-domains, which increases the leakage current of the SBT thin films. •Flexible polycrystalline SrBi2Ta2O9 thin films on Pt/mica substrates.•Ferroelectric domain structures with rectangular a-domains and elongated c-domains.•Enhanced ferroelectric and piezoelectric properties with c-domain distribution.•Leakage current characteristics improved by increasing distribution of a-domains.•Domain wall currents of 90o domain walls and 180o domain walls.