Brainchild of sisters Ilona Hamer and Peta Heinsen, this Australian label began in 2015 with a single swimsuit: an elegant black bikini. Now, it encompasses everything you could possibly want for a water-adjacent getaway: a collection of tops, briefs, and maillots that’s reliably first-rate. Matteau is guided by a slow fashion ethos and a commitment to details—romantic shirring, richly draped organic cotton, and gently figure-defining cuts.