Abstract: With the rapid advancement of modern underwater detection technologies, both detection accuracy and frequency coverage, particularly in the low-frequency range, have improved significantly. Naval acoustic stealth has traditionally relied on noise source control and propagation path control methods, such as raft isolation, damping treatments, mufflers, and anechoic tiles. While effective in attenuating noise in the mid-to-high frequency bands, conventional technologies such as anechoic tiles face inherent limitations in absorbing low-frequency sound waves due to the large wavelengths of these frequencies and the constraints imposed by limited structural thickness. This low-frequency bottleneck has become a critical barrier to further advancements in naval stealth, highlighting the urgent need for innovative solutions. Acoustic metamaterials, with their unique ability to control long wavelengths using small-scale structures, offer significant potential for ship vibration and noise control. This paper first reviews the limitations of traditional naval acoustic stealth strategies, then examines three representative types of sound-absorbing and insulating metamaterials: phononic crystals, thin-film metamaterials, and Helmholtz-type metamaterials, focusing on their physical mechanisms and engineering applications. Phononic crystals, based on Bragg scattering, can create bandgaps that block specific frequency ranges, showing promise in vibration isolation for ship power systems and structural sound insulation. However, challenges such as lightweight design and environmental adaptability remain. Thin-film metamaterials, which leverage negative effective mass to bypass the mass law, enable ultra-thin and lightweight low-frequency sound insulation, making them ideal for naval lightweighting requirements. However, issues related to pre-tension control and marine durability persist. Helmholtz-type metamaterials achieve broadband low-frequency absorption through acoustic siphon effects, multi-order resonance, and acoustic mass regulation, proving effective for compartment noise control. Nonetheless, challenges such as fabrication complexity and cavity clogging still need to be addressed. The paper also reviews recent advancements in underwater acoustic coatings, which play a pivotal role in the external stealth of naval platforms. Two primary types are discussed: inclusion-based metamaterials, which achieve broadband low-frequency absorption through local resonance while maintaining high pressure resistance, and film/plate-type metamaterials, which leverage zero effective mass characteristics to enhance low-frequency performance. Additionally, strategies for broadband design, including multi-unit coupling, bandgap coupling, gradient structures, and multimodal regulation, are summarized. Finally, the paper highlights future directions for naval acoustic metamaterials, including enhancing their resilience under extreme marine conditions, developing intelligent systems that integrate sound absorption and sensing capabilities, and accelerating their transition to engineering application. As sonar systems evolve toward low- and ultra-low-frequency detection, acoustic metamaterials are expected to become a cornerstone of next-generation naval stealth technologies, providing innovative solutions to enhance concealment and operational security.