The rotational structure in the vibrational transitions from v=0 to v=1, 2, 3, 4 of (HCl)-Cl-35 and (HCl)-Cl-37 is studied in Xe, Kr, and Ar matrices with high spectral resolution. A consistent set of rotational constants B-v for the vibrational levels v=0 to 4 is derived. B-0 decreases with the tightness of the cage from 9.78 cm(-1) in Xe to 8.83 cm(-1) in Ar for (HCl)-Cl-35 (gas phase 10.44 cm(-1)). The values for B-0 to B-4 decrease linearly with v due to the vibration-rotation-coupling constant alpha which increases from 0.37 cm(-1) in Xe to 0.479 cm(-1) in Ar (gas 0.303) according to the cage tightness. The splitting of the R(1) transition which originates from the hindering of rotation is analyzed in Xe using the T-2g-T-1u and T-2g-E-g transition energies. A comparison with force field calculations yields a dominant contribution of the sixth spherical harmonic Y-A1g(6) of the octahedral matrix potential. The modulation of the potential takes a value of K-6/B=17 which corresponds to a barrier for the rotation of 160 cm(-1). The splitting increases with the vibrational level v which can be interpreted as a weak admixture of the Y-A1g(4) spherical harmonic. A large isotope effect and a reduction of the T-1u-A(1g) transition energy [R(0)-transition] beyond the crystal field value are attributed to an eccentric rotation with a displacement of the center-of-mass of the order of 0.05 Angstrom. The vibrational energies omega(e) show an opposite trend with matrix atom size and decrease with polarizability from 2970 cm(-1) in Ar to 2945.4 cm(-1) in Xe (gas 2989.9 cm(-1)) while the anharmonicity omega(e)x(e) of the free molecule lies close to the Kr value and thus between that of Ar and Xe.