This preliminary comparative experimental study investigated the quasi-static axial crashworthiness of thin-walled aluminum square tubes incorporating multicellular ABS cores. Four ABS core configurations (E, J, N, and M) and three nominal ABS core wall thicknesses (1.0, 1.2, and 1.4 mm) were examined, with one specimen tested for each configuration–thickness combination. Crashworthiness was evaluated using peak crushing load (Pmax), mean crushing load (Pmean), energy absorption (EA), specific energy absorption (SEA), and crushing load ratio (CLR). Among the tested specimens, higher Pmax values were recorded at greater nominal ABS core wall thicknesses in each configuration series, whereas EA, SEA, Pmean, and CLR exhibited configuration-dependent and non-monotonic variations. N3 recorded the highest measured Pmax (72.48 kN), Pmean (53.39 kN), and EA (6.14 kJ), whereas E2 recorded the highest SEA (18.82 kJ/kg) and CLR (75.86%). All specimens exhibited progressive crushing without global buckling or fracture. Because no replicate tests were conducted and the aluminum-tube and ABS-core masses, ABS-core relative density, and volume fraction were not determined separately, the observed differences should be interpreted as preliminary comparisons among the twelve investigated hybrid specimens rather than as statistically confirmed or independently isolated effects of core geometry, wall thickness, or material quantity.