The report by Social Care Wales looked at the experiences of 10- to 17-year-olds from Wales who are being deprived of their liberty in secure accommodation across the UK.
This includes details of violent treatment within the centres and when they are being transported to secure accommodation, often far from their home.
The report found that a lack of secure beds in the devolved region means half are being locked up in homes outside of Wales, in England and Scotland.
One young interviewee, Jack, told the report authors how he was sent to a secure home in England against his will on his birthday.
This included being "wrestled" into the back of a car while he "didn't have a clue what was going on".
Another interviewee Megan said: "‘No-one gave me a warning that I was going into secure."
"I was at my [relative's] house. I got thrown in a van. I was covered in marks, and the geezer, before he shut the door, actually punched my [relative].
"I didn't know anything about it, I just had a social worker turn up and she was talking me through it, and then the next minute these men came up behind me and picked me up and threw me in the van, and I always just like, I didn't know what was going on.
"I thought I'd got kidnapped, like it was so scary. It was horrible."
During care young people told the report authors of their dislike for the environment, including locked doors, lack of free association and needing permission to use the toilet.
They are also concerned about the use of restraint in secure accommodation.
One young person interviewed called Mia describes being dragged violently into a locked empty room with no mattress or access to a toilet.
She said the secure care worker involved "had these massive hands as well, both his fingers were in my eyes when I was being dragged down the corridor, I couldn't see nothing.
"Like literally, it was horrible. I don't think he should have done that. Like putting fingers in kids' eyes so they can't see, being dragged down a corridor."
In addition, while 38 per cent of those interviewed said their experience in care after leaving secure accommodation was good, the same proportion described their life after leaving such care as difficult.
Young people are placed in secure children's homes as they are believed to be a serious risk to themselves or others, for criminal reasons or on welfare grounds.
Less than a quarter of homes that children from Wales are being sent to are able to solely cater for young people in secure accommodation for welfare reasons. This includes those who have mental health problems or have experienced severe trauma including bereavement, abuse and neglect.
The report found that life for most young people when they enter secure accommodation is "traumatic and difficult".
Young people felt that their confinement was "inappropriate", especially those being contained for welfare reasons and having to mix with those entering care via the criminal justice system.
Homes are too focused on containing children rather than offering specialist support, such as therapy, found the report.
However, the report does note that once children had settled, secure accommodation gave many a "consistent, regulated environment in which they felt safe".
The report focuses on 43 young people from Wales who were placed in secure accommodation between April 2016 and March 2018.
It calls for the creation of a national strategy across Wales to ensure young people with complex needs receive appropriate care.
This includes ensuring foster and residential care workers receive specialist training to meet the needs of those with challenging behaviour.
Early mental health support and more inclusive care planning is also needed. Support including mental health therapy, needs to continue after young people leave secure accommodation, recommends the report.
In addition, children need to be placed closer to home if appropriate and the "look and feel" of secure accommodation needs to improve to make it less austere.
"Being placed far from home has a negative impact on young people, their families and local authorities as it makes regular contact difficult and expensive," states the report.
"In knowledge of this, every effort should be made to place young people as close to home as possible."
Social Care Wales chief executive Sue Evans said: "While a third of the young people that we have information on are achieving positive outcomes, the rest are not doing so well.
"This report does not make for good reading, particularly the experiences of these young people in their own words. Sadly, the findings are not altogether surprising, given we are talking about the most vulnerable young people in Wales who account for one per cent of all those in care."
The report is now being presented to the Welsh government to consider.