About us

We are international specialists in the design, development and manufacture of injected and prefabricated soles. With over 25 years of experience, a production that exceeds three million pairs per year, and the trust of some of the biggest fashion brands in the world, we are known for combining excellence, innovation, impact and sustainability in one word: ISI.

Over 25 Years of History

Established in 1997, ISI – Indústria de Solas Injectadas, Lda – started in Felgueiras, Portugal, with a small idea, three employees, and an attitude focused on the future.

Over the years, we gained national and international notoriety, completed a variety of projects and built a solid reputation while increasing our team and production capacity. Today, we have two companies: ISI Soles and Uniflex. Together, we make 3 million pairs per year. We also have 130 specialized employees and the trust of countless clients and brands from around the globe.

Values that Set Us Apart

Innovation: From the design aligned with the latest trends to the use of innovative production technologies – such as 3D printing and flexible prototyping –, and a specialized team in ongoing training, we let go of the comfort of the status quo to embrace the future.

Excellence: More than just a core value, it’s a habit we practice every day. We only work with trusted suppliers, rely on qualified professionals, and implement robust processes to meet the highest standards of quality and the most demanding standards required by big brands and international groups – consistently.

Impact: Our impact goes well beyond our products. We create a positive and challenging work environment where our team engages in ongoing training, grows with us, and feels fulfilled. We support countless social and cultural projects. We celebrate protocols with schools and universities. We employ the latest industrial waste treatment methods and doubled down on recycling. And we aim to positively impact people and the planet.

Sustainability: In 2018 we became the first Portuguese company in our industry to be recognized for our international best practices regarding the environment, became ISO 14001-certified and, since then, we never stopped minimizing our environmental impact, rethinking our processes, and implementing evermore sustainable practices.

Mission and Vision

ISI’s mission is to create, develop and manufacture injected and premanufactured soles that blend a modern design, high-quality raw materials and a cutting-edge production process in a single product.

Currently, we produce 3 million pairs per year that travel the world and serve as the basis for the most popular footwear of some of the biggest names in the fashion industry.

But we don’t intend to stop here. We already have a production capacity of 4 million pairs per year that will allow us to continue to grow and take the ISI quality to even more clients and countries. 

We've recently launched a new company, Uniflex by ISI. It specializes in assembly insoles.