Bikini briefs by River Island - Made from a stretch swim fabric. - Low-rise, hipster cut. - Full, flattering back. - Adjustable self-tie sides. ABOUT RIVER ISLAND: River Island brings us an eclectic collection of fashion forward styles. Look out for vibrantly printed party dresses, feminine detailing, statement jackets and a covetable range of denim including skinny cut jeans and cute denim shorts, which sits alongside their directional footwear and swimwear range.