We present the first determination of the hadronic decays of the lightest exotic JPC=1-+ resonance in lattice QCD. Working with SU(3) flavor symmetry, where the up, down and strange-quark masses approximately match the physical strange-quark mass giving mπ∼700 MeV, we compute finite-volume spectra on six lattice volumes which constrain a scattering system featuring eight coupled channels. Analytically continuing the scattering amplitudes into the complex-energy plane, we find a pole singularity corresponding to a narrow resonance which shows relatively weak coupling to the open pseudoscalar–pseudoscalar, vector–pseudoscalar and vector–vector decay channels, but large couplings to at least one kinematically closed axial-vector–pseudoscalar channel. Attempting a simple extrapolation of the couplings to physical light-quark mass suggests a broad π1 resonance decaying dominantly through the b1π mode with much smaller decays into f1π, ρπ, η′π and ηπ. A large total width is potentially in agreement with the experimental π1(1564) candidate state observed in ηπ, η′π, which we suggest may be heavily suppressed decay channels.