Polyatomic molecules provide complex internal structures that are ideal for applications in quantum information science1, quantum simulation2, 3–4 and precision searches for physics beyond the standard model5, 6, 7, 8–9. A key feature of polyatomic molecules is the presence of parity-doublet states. These structures, which generically arise from the rotational and vibrational degrees of freedom afforded by polyatomic molecules, are a powerful feature to pursue diverse quantum science applications7. Linear triatomic molecules contain ℓ-type parity-doublet states in the vibrational bending mode, which are predicted to exhibit robust coherence properties. Here we report optically trapped CaOH molecules prepared in ℓ-type parity-doublet states and realize a bare qubit coherence time of T2*=0.8(2)sdocumentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} begin{document}$${T}_{2}^{* }=0.8(2),{rm{s}}$$end{document}, which is longer than the 0.36 s lifetime of the bending mode10,11. We suppress differential Stark shifts by cancelling ambient electric fields using molecular spectroscopy and characterize parity-dependent trap shifts, which are found to limit the coherence time. The parity-doublet coherence times achieved in this work are a defining milestone for the use of polyatomic molecules in quantum science. Optically trapped CaOH molecules in parity-doublet states achieve coherence times exceeding vibrational lifetimes, which are a defining milestone for the use of polyatomic molecules in quantum science.