Seaweed packaging uses alginate and carrageenan extracted from farmed macroalgae, sometimes blended with other biopolymers, to make films, coatings and a small number of rigid parts. Seaweed needs no land, fresh water or fertiliser to grow, which is the main environmental argument for it.
It replaces flexible films and polybags, sauce sachets and pipettes, grease-proof coatings of PE and per- and polyfluoroalkyl substances (PFAS) on takeaway boxes, straws, cutlery, window film on envelopes and single-serve water pods. Notpla (UK) sells Ooho edible pods, a seaweed coating for takeaway boxes, film and a pipette, and says millions of units have shipped across eight EU countries. Sway (US) makes TPSea Flex film, named a TIME Best Invention in 2025 and certified TÜV AUSTRIA OK compost HOME and INDUSTRIAL. Loliware (US) licenses SEA Technology resins for straws and cutlery that run on standard plastics machinery, Evoware (Indonesia) makes edible sachets for dry goods, and B'ZEOS (Switzerland and Spain) supplies seaweed pellets for films, coatings and moulding.
The evidence base is thin. The best documented outcome is the Just Eat trial with Notpla, which avoided about 30,000 plastic boxes and 46,000 sachets; Notpla's claim of 70 percent lower carbon dioxide equivalent (CO2e) per unit is a vendor figure without a published independent life-cycle assessment (LCA). End of life is home compostable or edible for Notpla and Evoware products, and Sway holds the TÜV HOME mark.
Drawbacks: the films are moisture sensitive and have short shelf lives; many seaweed products are blends with other polymers that are not always disclosed (Sway states TPSea Flex contains non-renewable certified home-compostable polymers); production volume is tiny against global film demand. Cost: a Notpla burger box was about £0.23 a unit, comparable with paper, and a 2026 trade estimate puts seaweed film at US$2,200 to 2,800 a tonne, close to parity for thin films where plastic taxes apply, but Notpla itself has said seaweed may never match commodity plastic on price.