Stella McCartney continues to set the standard for sustainable fashion with her most eco-friendly trainers to date. The updated S-Wave sneakers, part of the Autumn 2025 collection, use a carefully selected mix of recycled, biobased, and compostable materials. These innovations mark a significant step towards fully circular footwear.

From Cinnamon-Scented Soles to Recycled Uppers

The highlight of the new S-Wave is its BioCir Flex sole. This cinnamon-scented bioplastic was developed in collaboration with materials science company Balena. Made from non-toxic, plant-based materials, the sole performs like traditional plastic but breaks down like organic matter. It is both industrially compostable and recyclable, offering designers a viable alternative to fossil-based plastics such as TPU and EVA.

Previously, many trainers—even sustainable ones—relied on plastic soles. These are hard to recycle and contribute to microplastic pollution. BioCir Flex solves that problem by combining flexibility and durability with end-of-life options that are better for the environment.

A Holistic Approach to Circular Design

The trainer’s upper is just as considered. It features recycled mesh panelling and an engineered knit made from recycled polyester. Recycled alter suede overlays add strength and structure. Inside, the lining is made from hemp, and the label is spun from organic cotton.

To enhance comfort and flexibility, the shoe includes a vulcanised sole made from recycled rubber. These materials come from both post- and pre-consumer sources. That means they reuse existing textiles and industrial waste, helping to reduce reliance on virgin fossil materials.

End-of-Life Strategy and Industry Impact

The S-Wave is designed with end-of-life in mind. When the sneakers wear out, customers can return them to Stella McCartney. The components will be separated. While the soles can be composted, the preferred option is recycling them into new soles. This reduces the need for producing new material from scratch.

Although the price point is high (£550), the product shows what’s possible when brands invest in material innovation. For fashion and product designers, it offers a clear example of how to combine circularity, performance, and style.

As demand grows for sustainable products, materials like BioCir Flex may soon move beyond high-end capsules and into mainstream design.

Source: Fast Company & Stella McCartney
Photos: Stella McCartney / Balena