Sway TPSea Seaweed-Based Compostable Packaging

Sway is a California-based materials company of material scientists and designers that makes compostable packaging from seaweed. It targets bags, wrappers and pouches, a category of thin flexible plastic that is rarely recycled.

Its TPSea resin is a patented, certified 100% biobased pellet with seaweed as the main ingredient; it is melt processable, so manufacturing partners compound and extrude it into pellets and films on standard plastic equipment. TPSea Flex blends TPSea with home compostable polymers to make strong, moisture-resistant film for polybags and die-cut handle bags, and Firstwave is a transparent cast film made from ocean-farmed seaweed and plants. Seaweed is sourced from suppliers in Indonesia, Chile, Puerto Rico, Mexico and Madagascar. Customers are apparel, footwear, outdoor and food brands.

• TPSea resin: patented, 100% biobased seaweed pellet for melt processing.
• TPSea Flex film: seaweed blend film for polybags, mailers and retail bags.
• Firstwave film: transparent cast film made from ocean-farmed seaweed and plants.
• Standard equipment: compounded and extruded by partners on conventional plastic lines.
• Compostability: home and industrial compostability certified by TÜV Austria.
• Global seaweed supply: vetted suppliers including farms in Indonesia.

Garment and footwear factories in Vietnam producing for Western brands can replace plastic polybags with TPSea Flex bags. E-commerce sellers can use compostable seaweed mailers for apparel shipments. Local film extruders can partner to compound and convert TPSea resin for regional brands.

Sway materials are certified 100% biobased (TPSea and Firstwave) and are certified for home and industrial compostability by TÜV Austria, giving brands an end-of-life option for flexible packaging that is rarely recycled. Because TPSea runs on traditional plastic processing equipment, converters can produce it without new lines. Brands such as prAna, Faherty and Burton have rolled out or piloted the packaging.

Fashion and e-commerce brands are under pressure to remove plastic polybags from their supply chains, and extended producer responsibility rules are expanding in many markets, including Vietnam. Southeast Asia is both a major garment manufacturing hub and a large seaweed producer, which positions the region for seaweed-based packaging supply.

California-based company led by co-founder and CEO Julia Marsh. Raised a 5 million USD seed round in 2024. Named in TIME Best Inventions of 2025 and Fast Company World Changing Ideas 2024, and listed in Norrsken 100 in 2026. Announced a partnership with Charter Next Generation on seaweed-based biomaterials in 2025.