Next month, the German sportswear will begin selling three new editions of its popular UltraBoost shoe, all made from plastic debris found in the ocean. On average, the shoes reuse 11 plastic bottles per pair and feature laces, heel lining and sock liner covers that are made from recycled materials.

Debuting in retail stores and online on May 11, the shoes will help Adidas reach its goal of creating 1 million pairs of UltraBoost sneakers using ocean plastic this year. While Adidas has used recycled polyester and sustainable cotton in previous products, most of these eco-friendly production runs have been relatively small.

In November, Adidas unveiled the company’s first performance products—soccer jerseys and running shoes—that were mass produced with plastic found in the oceans. The gear was a limited release, but it resonated with shoppers: Adidas says the first UltraBoost Uncaged Parley was the best-selling shoe at the company’s newly opened store on 5th Avenue in New York City.

High-performance shoes made from marine plastic are part of a larger sustainability push by the company. Last year, Adidas switched from plastic bags to paper in its retail stores and, as a result, said it has now eliminated about 70 million plastic shopping bags. Adidas has also made progress in its efforts to cut per-employee water usage and use more cotton sourced in an environmentally friendly manner. Meanwhile, rival Nike (NKE) has made strides to become more sustainable by reusing wasteful materials to make new consumer products.

Beyond the use of recycled plastics, shoe makers have become more innovative and experimental in how they manufacture, source materials, and use technology to make sneakers. A short-list of new initiatives include Adidas’ 3D-printed shoes, Reebok’s use of futuristic liquid material and 3D drawing, Nike’s personalized marathon running shoes for elite athletes, and Under Armour’s (UAA) connected footwear with built-in sensors.