The protonation sites of phenol are investigated by IR photodissociation spectroscopy of protonated phenol complexed with one and two Ar ligands, PhH+-Ar-n (n = 1, 2), in the vicinity of the O-H stretch fundamentals. The complexes are produced in a supersonic expansion of Ph, H-2, and Ar combined with electron impact ionization. The vibrational analysis of the TR spectra unambiguously reveals the presence of at least two PhH+ isomers in the expansion: protonation occurs at oxygen and at the aromatic ring (in para and/or ortho position). This observation represents the first spectroscopic evidence for the existence of several PhH+ isomers in the gas phase. The Ar ligands in PhH+-Ar-n prefer hydrogen bonding over other binding sites. Quantum chemical calculations support the interpretation of the experimental data and provide further insight into the relative stability of various PhH+ isomers and their complexes with Ar.