<p>Comparative experiments were conducted on broken soft and low-permeability (BSLP) coal particles under varying water saturations (0–100%) to elucidate the differential effects of direct and indirect thermal contact during liquid nitrogen (LN₂) borehole freezing on the pore structure and methane adsorption behavior of BSLP coal. Pore evolution and adsorption characteristics were analyzed using low-temperature gas adsorption, high-pressure methane adsorption, and fractal theory. Direct freezing, dominated by a thermal shock-induced fracturing mechanism, increased the micropore and Langmuir volumes by 56.6% and 23.2%, respectively, and reduced the adsorption affinity (<i>b</i> value) by 70.6%. Indirect freezing, governed by a frost heave-induced progressive connectivity mechanism, increased the micropore volume by 27.2%, with a moderate <i>b</i> value reduction of 32.0–44.6%. Water saturation was a critical regulatory variable, acting as the sole frost heave agent governing pore modification during indirect freezing, while enhancing the thermal shock effects as an auxiliary medium during direct freezing. Ice crystals block pore throats at low water saturations (10–30%), reducing accessible pore space, whereas at high saturations (60–100%), abundant pore water generates strong frost heave forces that drive comprehensive pore expansion. This study revealed the differences in coal reservoir modification under distinct LN₂ contact modes, providing theoretical guidance for optimizing borehole protection strategies in BSLP coal seams.</p>