Floaters with exposed surfaces are essential for applications in heterogeneous catalysis, microdetectors, and solar evaporation. Conventional floaters, however, rely on specific low-density or hydrophobic materials, restricting their adaptability. This study introduces a topological design principle, enabling dense, hydrophilic materials to float stably on water. The proposed hydrophilic cellular sheet (HCS) features a water-attractive substrate patterned with a crown-shaped pore array, fabricated via digital light processing. These unique pores trap air effectively, providing exceptional buoyancy. The modular design of the HCS allows for versatile plug-in functionalities by utilizing the pores as reservoirs for functional beads. The combination of multi-HCSs enables on-water information encryption and decryption. Furthermore, the HCS demonstrates potential as supporting devices in triboelectric nanogenerators, promising in wave energy harvesting. This work establishes a versatile platform for designing adaptable floaters with integrated functionalities, expanding their utility in areas, such as interface carriers, encryption devices, and renewable energy collection.