I just posted a question about eco-friendly wetsuits, which lead me to this thread. Arena seems to be one of the more transparent companies: unlike, say, Tyr, Arena has a whole section of its website devoted to fair labor and environmental concerns.
I haven't found any of the big swim companies listed on auditing sites like goodonyou.eco or donegood.co. But I have found these cool-looking suits made from plastic bottles by a UK company called Batoko. They're not made for training per se, but they look nice!
I believe suits are much more ecofriendly than the body it's worn by.
I believe suits are much more ecofriendly than the body it's worn by.