The textile fabric interface between the human body and the environment is currently being promoted by the clothing industry as a route to improve human health and comfort. Ternary blends of environmental waste materials, including recycled plastic bottles (poly(ethylene terephthalate), rPET), oyster shell powder (OSP), and silica aerogels (SAGs), were used to fabricate composite textiles. The structural, mechanical, and thermal properties of the resulting textiles were evaluated together with the water-contact angle and antibacterial effects. rPET textiles typically exhibit high hydrophilicity, poor thermal conductivity, and no antibacterial effects. Incorporating SAG and OSP as fillers in the processed filaments significantly enhanced the functional performance of rPET textiles. The addition of SAG enhanced hydrophobicity and decreased thermal conductivity. This allows better temperature regulation by rPET/SAG textiles. The addition of OSP resulted in a composite material with antibacterial properties (rPET/ASAG). The rPET/ASAG textiles boast excellent tensile strength, insulating effects, temperature regulation, water resistivity, laundering durability, and antibacterial properties. In addition, the developed rPET/SAG and rPET/ASAG fabrics are amenable to large-scale production and implementation in a variety of textile products.