The aim of this study was to evaluate the effect of short-term thermal exposure on the mechanical performance of a hybrid composite reinforced with carbon and aramid fibres. Composite panels were manufactured using the vacuum bagging technique and subsequently machined into specimens for puncture resistance, tensile, and three-point bending tests. The results showed a progressive reduction in mechanical properties relative to the unexposed reference state, indicating thermal degradation of the composite structure. The material exhibited good thermal insulation capability, particularly when heated from the aramid side. The influence of fibre type was found to be significant: specimens exposed from the aramid fibre side retained higher puncture resistance and tensile performance compared to those exposed from the carbon fibre side, suggesting greater thermal stability of aramid fibres under the tested conditions. In contrast, bending strength showed the highest sensitivity to thermal exposure, with a substantial decrease relative to the initial (unexposed) values. Microscopic analyses confirmed that the observed mechanical degradation was associated with matrix decomposition, delamination, and microcrack formation. The obtained results contribute to a better understanding of the behaviour of hybrid composites under thermal loading and may support the design of structural materials for applications requiring both load-bearing capacity and resistance to elevated temperatures. The results obtained are applied in the design of structural components used in the aerospace, automotive, and defense industries, where materials are exposed to high temperatures and fire. They can also be used in the development of protective systems, such as thermal shields and ablative coatings. Furthermore, this research supports the development of more resilient composites for use in special-purpose vehicles and infrastructure exposed to extreme operating conditions.