Traditionally, women wore serge or dark flannel bathing dresses in the early Victorian era, but by the 1860s, two-piece belted costumes replaced earlier styles. Amelia Bloomer, who urged women to wear them a decade earlier, had designed a swimwear bodice top that looked like a jacket and a bottom part that looked like three-quarter trousers.
Victorian bathing outfits were still cumbersome but were more attractive and practical than earlier bathing clothes.
Also, check the evolution of swimsuits.