This work aims to investigate the local structure of mesoporous silica of the type SBA‐15 functionalized with propylphosphonic acid groups by means of an extensive solid‐state NMR spectroscopic study. Here, the functionalized SBA‐15 samples are obtained by a one‐step synthetic method that allowed us better control over the loading and the distribution of the surface functions. In addition to NMR spectroscopy, the materials are characterized by X‐ray diffraction, nitrogen adsorption–desorption and transmission electron microscopy. The 29Si, 13C, 31P and 1H one‐dimensional NMR spectroscopic results are discussed according to the nature of the functional groups in dry and wet materials. This paper proposes a rigorous approach that shows possible hydrogen bonding between adjacent phosphonic acid groups in dry SBA‐15, from the comparative study with an alkylphosphonic acid material. This outcome was demonstrated by two‐dimensional NMR spectroscopic solid–state experiments, including the use of 1H–1H spin‐diffusion exchange experiments, 31P–31P double quanta and an original pulse sequence that corresponds to 31P–1H–1H–31P correlation experiments.