In the early to mid-twentieth century, women had limited opportunities to develop and practice as scientists and, when they did, were often marked out: regarded as odd or remarkable because they were women with scientific commitment, in contrast to their male counterparts. Opportunities for women in freshwater science arose in Britain in interconnected institutions centred on the Freshwater Biological Association (FBA) founded in 1929. Several women scientists, pioneers in their fields, were nurtured by the FBA, such as the early freshwater researchers Penelope Jenkin, Marie Rosenberg and Winifred Frost, the two latter being the FBA’s first professional women naturalists. Several universities, such as Queen Mary College, University of London, gave opportunities to women freshwater scientists and had direct links to the FBA. Opportunities also arose for women scientists in British colonies. Other researchers who achieved distinction in their field were also products of the FBA and its imperial and university networks: Rosemary Lowe, Winifred Pennington, Winifred Frost, Carmel Humphries and Maud Godward, for example. We argue that the FBA encouraged scientists in relatively new scientific fields for the most part irrespective of gender. This is notable in a period when women scientists were treated with prejudice in scientific culture generally.