Geometrically frustrated triangular-lattice antiferromagnets exhibit a delicate competition between magnetic order and quantum spin liquid (QSL) behavior, with the Yb-based delafossite family AYbX₂ providing a structurally clean platform for exploring this physics. Here, we report a comprehensive study of single-crystal TlYbS₂ using DC magnetization, AC susceptibility, electron spin resonance (ESR), and specific heat measurements extending from room temperature to the millikelvin regime. Single-crystal X-ray diffraction confirms a trigonal R3̄m structure comprising well-separated triangular layers of Yb³⁺ ions with no detectable site disorder. At zero field, a weak thermodynamic anomaly is observed near 530 mK, which may indicate the onset of a weakly ordered state similar to that reported in KYbSe₂. Below 300 mK, the zero-field magnetic specific heat follows C_(rm m)∝ T^(1.8), close to a quadratic temperature dependence, in contrast to the linear temperature dependence reported for the sister compound TlYbSe₂, which has been described in terms of the interplay between spinons and thermally excited gauge-flux excitations. Magnetization and ESR measurements establish pronounced easy-plane magnetic anisotropy, with g_⊥/g_∥ ≈ 6.9. The anomaly near 530 mK exhibits a strongly anisotropic response to magnetic field. For H⊥ c, it remains visible up to approximately 2 T and continuously evolves toward a field-induced ordered phase above approximately 2.5 T, followed by a sequence of field-induced phases that includes a 1/3 magnetization plateau between approximately 5 and 8 T and full polarization near 17 T. In contrast, for H∥ c, the anomaly weakens and is suppressed near 3 T, consistent with the recently reported confinement–deconfinement transition from an ordered state to a field-induced QSL.