Keel Labs, a North Carolina-based startup, and eco-conscious California brand Outerknown have teamed up to debut the first commercial launch of Kelsun, a seaweed-based fiber. This partnership aligns with both brands' dedication to ocean sustainability and responsible fashion.

Outerknown, co-founded by pro surfer Kelly Slater and designer John Moore, first introduced the popular Blanket Shirt in 2016. Known for its sustainable design and vintage softness, the shirt remains a brand favorite. The new version, made from an organic cotton and Kelsun yarn blend, maintains the original’s comfort while introducing innovative, planet-friendly materials.

Kelsun, developed as a sustainable replacement for traditional textile fibers, is 100 percent biobased and biodegradable. Made from over 75 percent seaweed biopolymer, the material breaks down naturally in about 60 days. Keel Labs ensures responsible seaweed sourcing, adhering to sustainability guidelines and local harvesting practices.

Keel Labs' co-founder and CEO, Tessa Callaghan, expressed excitement about working with Outerknown, noting their shared commitment to sustainability and a love for the sea. The collaboration brings Keel Labs’ mission to create environmentally friendly products from ocean resources to life.