Water-stable proton-conducting materials owning excellent performances at ambient temperatures are currently one of the crucial challenges. Herein, four water-stable three-dimensional polyoxometalate-based rare-earth organic frameworks have been successfully synthesized and formulated as H­{Ln4(L)2(H2O)21[Zr3(OH)3(PW9O34)2]}·15H2O (1–3) (Ln = La (1), Ce (2), Pr (3); L = 3,5-pyridine dicarboxylic acid), which are the first examples of MOFs constructed by a zirconium sandwiched polyoxoanion. There are abundant coordinated water molecules functionalizing the PrIII centers, and simultaneously, plenty of lattice water molecules are fitted into the channel of the framework. A continuous H-bonding network is found between the architectures and plays an important role in stabilizing the structure. Benefiting from the consecutive H-bonding networks, compounds 1–3 showed high proton conductivities at ambient temperature (up to 1.05 × 10–3 S·cm–1 under 98% RH) by a synergistic effect of the combined components.

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