We study quantum-secure covert-communication over lossy thermal-noise bosonic channels, the quantum-mechanical model for many practical channels. We derive the expressions for the covert capacity of these channels: Lno-EA, when Alice and Bob share only a classical secret, and LEA, when they benefit from entanglement assistance. Entanglement assistance alters the fundamental scaling law for covert communication. Instead of Lno-EA√n−rno-EA (n), rno-EA (n) = o(√n), entanglement assistance allows LEA√n log n − rEA (n), rEA (n) = o(√n log n), covert bits to be transmitted reliably over n channel uses. However, noise in entanglement storage erases the log n gain from our achievability; work on the matching converse is ongoing.