For the development of porous materials with improved transport properties, a key ingredient is to determine the relations between growth kinetics, structure, and transport parameters. Here we address these relations by studying solute diffusion through three-dimensional porous films produced by deposition models with controlled thickness and porosity. A competition between pore formation by lateral particle aggregation and surface relaxation that favors compaction is simulated by the lattice models of ballistic deposition and of random deposition with surface relaxation, respectively, with relative rates proportional to p and 1 − p. Effective diffusion coefficients are determined in steady state simulations with a solute source at the basis and a drain at the top outer surface of the films. For a given film thickness, the increase of the relative rate of lateral aggregation leads to the increase of the effective porosity and of the diffusivity, while the tortuosity decreases. With constant growth conditions, the increase of the film thickness always leads to the increase of the effective porosity, but a nontrivial behavior of the diffusivity is observed. For deposition with p ≤ 0.7, in which the porosity is below 0.6, the diffusion coefficient is larger in thicker films; the decrease of the tortuosity with the thickness quantitatively confirms that the growth continuously improves the pore structure for the diffusion. Microscopically, this result is associated with narrower distributions of the local solute current at higher points of the deposits. For deposition with p ≥ 0.9, in which the films are in the narrow porosity range ∼ 0.65 − 0.7, the tortuosity is between 1.3 and 2, increases with the thickness, and has maximal changes near 25%. Pairs of values of porosity and tortuosity obtained in some porous electrodes are close to the pairs obtained here in the thickest films, which suggests that our results may be applied to deposition of materials of technological interest. Noteworthy, the increase of the film thickness is generally favorable for diffusion in their pores, and the exceptions have small losses in tortuosity.