<p>Traditional topology optimization methods struggle to effectively address the issues of accurately capturing, representing and manufacturing the fluid–structure interaction interfaces of continuum structures caused by the design dependence of fluidic pressure loads. To tackle this challenge, this paper proposes a novel topology optimization approach tailored for design-dependent fluidic pressure-loaded continuum structures based on the three-field floating projection topology optimization (Three-field FPTO) method. A linear material interpolation model with Darcy’s law featuring a drainage term is used to accurately describe the coupling interfaces under fluid pressure loads. Besides, unlike the conventional penalty-based methods that use density interpolation models combined with penalty factors to obtain clear topological configurations, the proposed non-penalty topology formation mechanism driven by implicit floating projection functions is used to gradually drive the update of design variables toward a clear 0/1 topological distribution. Furthermore, by employing a smooth level set function and an equivalent representation convergence criterion, the smooth designs with a clear and smooth boundary, stable objective performance, and direct applicability to 3D printing are obtained. The method can be easily extended to the robust formulation, which obtains the eroded, intermediate, and dilated designs with the same topology to address potential configuration defects under low volume fractions. Some 2D and 3D benchmark numerical examples confirm that the presented novel approach can precisely identifies the coupling interfaces, yielding smooth topologies with superior objective performance, more compact configurations, improved impermeability, and more reasonable pressure distributions. This work provides some valuable insights for multi-physics topology optimization and lays a foundation for the design of pressure-loaded composite engineering structures.</p>