Twenty one children in Wales were considered to be potential victims of exploitation last year, according to National Crime Agency figures.
Children’s charity Barnardo’s Cymru is raising awareness to mark International Missing Children’s Day on Thursday.
Its report with Glyndŵr University last year said 80% of children deemed at significant risk of sexual exploitation had previously gone missing overnight.
The charity said it is a “hidden form of abuse”.
Barnardo’s Cymru’s Missing Service in south Wales has four child sexual exploitation (CSE) and missing practitioners across the police force area.
They work with children and young people who have gone missing from home, even if they have only been away a few hours.
Together with the police they work to identify and help vulnerable children at risk of being targeted for child sexual exploitation through gangs and individual perpetrators.
Practitioner Sarah-Jane Davies said: “This is a particularly hidden form of abuse which can often happen within the context of relationships.
“Young people can be targeted online, at a party or elsewhere in the community.
“Often adults will target young people due to their vulnerabilities and look to employ grooming tactics which are designed to build a trusting relationship with the child for the purpose of sexual exploitation.
“Social media can compound the risks to young people. Many are unaware of the risks associated with sharing images and personal information online.”
Ms Davies added: “Every young person has a different story and often it is difficult for them to tell it, particularly if they don’t trust those around them.
“Many young people are unable to recognise that they have been groomed or exploited.”
Awareness events have been held for Police Community Support Officers to be better equipped at identifying young people who are vulnerable or a victim of CSE.
NSPCC Cymru urged people to sign up to the Child Rescue Alert scheme to help find missing children as soon as possible.