Thought to be one of the most sustainable retailers on the high street, Arket has a great range of swimwear, of course! Made from recycled polyamide, similar to the popular Econyl, this Seamless Bikini Top (£25) and Seamless Bikini Briefs (£19) set is a more environmentally friendly option than your standard high street bikini and is sure to make you stand out on the beach this summer.