Campaigners called for more work to raise awareness, amid concerns women are not reporting incidents because they do not know about the law.
Crown Prosecution Service (CPS) statistics show 16 men have been convicted of 48 upskirting offences since April 2019 in England and Wales, including four who were given prison sentences.
Data shows the vast majority of the offences (33) took place in supermarkets and shops, with nine on public transport, five in the street and one in a school.
The law was introduced after Gina Martin lobbied the government for two years when she was unable to prosecute a man who took a picture up her skirt at a music festival.
Those convicted in England and Wales face prison sentences of up to two years, although the crime can also be punished with a fine on summary conviction.
Siobhan Blake, the CPS lead for sexual offences, said: “It has now been a year since this degrading practice became a specific criminal offence but women continue to be violated as they go about their daily lives.
“This appears to be a particular problem in shops and on public transport, where predatory men are concealing devices to take pictures up women’s skirts.
“This is a serious crime and I am very pleased to see police and prosecutors making regular use of this legislation.”
The NSPCC described the law as a “really good step forward” in offering a route to justice for victims and broadening understanding of what sexual abuse is.
But the charity said there remained the need for greater education in schools about what amounts to abuse in an effort to stop teenagers sharing harmful images.
Alana Ryan, senior policy and public affairs officer at the NSPCC, said: “We are beginning to realise how much of an impact technology is having.
“This law change is really important because it puts a spotlight on that kind of technology and it makes it very clear that taking an image and sharing it is not acceptable.
“It’s really important that we have a legal criminal framework for adult offenders but also an understanding that young people need more education to understand what is and isn’t abuse.”
A schoolgirl who had indecent pictures taken of her without consent two years ago said many young people failed to understand the seriousness of upskirting.
Morgan, now 17, told the Press Association news agency: “I think people think it is a bit of a joke.
“Some people don’t appreciate the seriousness of it. Now there is a law, if people knew they could go to prison for two years, it might put them off.
“I think the law is fine but it’s the awareness that’s needed – people need to be taught from a really young age that this is wrong, if you were to do this, this is the punishment you will get.”
The teenager, from Birmingham, was 15 when a man took pictures of her without her knowledge. He was convicted of voyeurism, before the dedicated upskirting law was introduced.
Ms Ryan said the roll-out of new relationships and sex education at schools from September will “help create the space for schools to talk about toxic cultures and harassment”.
Additional reporting by PA