When you’re shopping for swim diapers, look for polyester materials that are recycled or bio-based. Even better, keep an eye out for plant-based material like lyocell. Avoid neoprene, due to its harm to the environment and its manufacturing hazards to humans. Finally, look for certifications like OEKO-TEX and Plastic Neutral that signify material safety and more responsible plastic production practices. 

For the eco-conscious (and wallet-conscious) parent, reusable swim diapers offer the chance to cut down on consumption, and ultimately shipping, packaging, and landfill waste, though they typically have a higher upfront cost.

Ingredients

Polyethylene terephthalate (PET) and r-PET

Similar to many disposable diapers, swim diapers - both disposable and reusable - rely heavily on polymers. Polyethylene terephthalate, more commonly known as PET (and often referred to simply as polyester), is the most common thermoplastic polymer, used regularly for things like bottles, packaging, and textiles. In 2016 the estimated annual global production of PET was 56 million tons. Most PET is derived from petroleum oil, a non-renewable resource, and plastics-based textile production uses approximately 342 million barrels of oil annually. Additionally, although polyester clothing generally consumes less water and energy during care than other textiles, it has been shown to release microplastics with every wash. As of 2021, it was estimated that 5 million tons of PET enter the ocean each year. Sadly, the amount of PET is on track to surpass the number of fish in the ocean within three decades. 

Although scientists have recently discovered bacteria that can break down polymers, the practice is not yet widespread. So, the next best eco-friendly alternative is to use recycled PET, or r-PET. R-PET is produced when plastic bottles are cut into small pieces which are then extruded into material for a new product (like a swim diaper!). Millions of plastic bottles are purchased every minute, and unless they are given a second-life by becoming r-PET, they’ll end up in landfills where they take hundreds of years to decompose. Textiles derived from r-PET also use less energy and up to 90% less water when produced. 

Polyurethane laminate (PUL) and Thermoplastic polyurethane (TPU)

Additional polymer compounds often found in swim diapers include polyurethane laminate (PUL) and thermoplastic polyurethane (TPU). Polyurethane is used to create breathable, light, waterproof material. TPU offers an extra eco-friendly advantage, because unlike PUL, which is formed through a chemical bonding process, it is bonded by heat alone. This makes the production free of toxins and more efficient. Thermoplastic composites like TPU have higher than average recyclability and environmental resistance compared to other polymers. As TPU market share increases - it's expected to reach a whopping $3.81 billion by 2028 from 2.32 billion in 2021 - it's more important than ever to invest in innovative TPU composites that are biodegradable or recycled. Recreation brands are already beginning to lead the way, decreasing carbon emissions by 89% in certain products by relying on recycled TPU, and replacing polyvinyl chloride with bio-based TPU that can biodegrade as quickly as 3-5 years. 

Lyocell

The plant-based fabric lyocell gets its name due to being a cellulosic fiber. Other names that might show up on packaging include its brand variations including Tencel and Newcell. Lyocell has been around for nearly 30 years, but is gaining popularity and recognition recently as mainstream consumers show increasing concern for the environment. In order to produce the material, wood is crushed into pulp and dissolved. Once lyocell fibers are turned into fabric, you have a miraculous product made without toxins, that absorbs 50% more than cotton while using half as much water during production, uses a dissolving agent of which 99.5% can be used repeatedly, and can be made from highly renewable resources like eucalyptus trees and bamboo. Just be sure to watch out for greenwashing, because the eco-friendliness of lyocell still depends on responsible sourcing and what additional materials it is paired with. 

Neoprene

If there’s a material to avoid for the eco-aware swim diaper seeker, it's neoprene. This synthetic rubber comes from limestone or petroleum, both nonrenewable resources, and is non-biodegradable. It's estimated that 380 tons of neoprene get discarded every year. Furthermore, manufacturing plants emit dangerous levels of a poisonous gas called chloroprene, recognized by the EPA and CDC to be strongly linked to cancer and vital organ damage.

Plastic Neutral

Similar to carbon neutral, a plastic neutral certification means that the same amount of plastic used to produce a product is removed by a company from the ocean or nature. Plastic neutrality is a starting point for decreasing the environmental harm of plastic use, although it's not a solution. Because plastic is non-biodegradable, some companies are promising to transition to completely plastic-free.

Certifications

Here are some certifications to look for when shopping this category.