For swimsuits - bikinis - I go for Bottega Veneta (designed by Tomas Maier), Louis Vuitton cruise and Eres.
If you buy from the Eres boutique, you can mix and match tops and bottoms both styles and sizes to suit you best.
For Christmas my husband bought me a cool Gucci bikini with insect print and a navy and red elastic bow detailing which is super cute as well as practical for swimming in!!!