The results of magnetic studies and Mössbauer spectroscopic investigations are reported for the stannides TbRhSn and DyRhSn crystallizing in the hexagonal ZrNiAl-type structure. The polycrystalline samples of these ternary intermetallics were synthesized by arc melting from metallic precursors. Detailed ^{119}Sn Mössbauer spectroscopic studies are used to investigate the hyperfine interactions and their temperature evolutions at places occupied by the diamagnetic tin nuclei. Magnetic properties of DyRhSn and TbRhSn were studied by AC/DC magnetometry in a wide temperature range. The results show that both compounds are magnetically ordered at low temperatures. DyRhSn is a non-collinear antiferromagnet with the Néel temperature T_{N} = 7.5 K, whereas TbRhSn undergoes a transition from a paramagnetic to an antiferromagnetic state at T_{N} = 20.2 K. An additional transition at T_{SR} = 10.3 K is detected for TbRhSn which corresponds to some changes in the magnetic moments ordering. The role of the magnetostriction effect in the evolution of the hyperfine parameters and its influence on the observed TbRhSn Mössbauer spectra is discussed. Triangular-like antiferromagnetic arrangements with rare-earth magnetic moments lying in the hexagonal plane are proposed for both compounds at very low temperatures.