It depends on the feminist.
The majority of feminists support sex workers, recognizing it's a womans choice what to do with her body and that it's important to protect sex workers from exploitation and abuse - although it also recognizes many women don't want to be sex workers: 'women make their own choices, but not always under circumstances of their own making'. Supporting sex workers includes those who don't want to do sex work but feel they have to in order to survive (supporting them while in sex work so they're protected from abuse, but also in looking at factors that put women in this position to begin with) or those sold into sex trade.
Supporting sex workers doesn't necessarily mean a person is pro-sex-work though. Some feminists see sex work as empowering but many are against sex work on the basis that within our society/culture sex work is about exploitation of women in general: it is men looking to use women for sex, objectification and commodification of women. Sex workers make the choice to benefit from a culture that mistreats women, feminists can support their choice while thinking critically about these choices.
There's a world of differnce between choice feminists, critical feminists, and SWERFs (sex work exclusionary feminists) - but for the record most feminists reject SWERFs as they are not just critical of sex work but often wish harm on sex workers.