Families face a struggle to find summer holiday childcare as councils across Britain report a lack of places.
In Wales and the east of England, none of the councils responding to a Family and Childcare Trust survey, said it had enough places for all age groups.
Average holiday childcare fees are down slightly on 2015 but remain 20% higher than in 2010, the study found.
Families face a summer of "high costs and limited choice", said trust's chief executive, Julia Margo.
The report looks at the prices and availability of holiday childcare for groups of children, such as holiday clubs, play-schemes or summer projects, in England, Scotland and Wales.
"Holiday childcare is an essential part of our country's infrastructure, enabling parents to juggle their caring obligations and work during the school holidays," says the report.
"Despite the importance of holiday childcare, too many families struggle to find local provision that they can afford."
The trust sent a survey to 205 local authorities in England, Wales and Scotland in May and 177 responded.
The results suggest that overall only 12% of local authorities have enough holiday childcare available for all age-groups.
Of the local authorities who responded in England the figure was 13%, in Scotland 22% and in Wales there were no authorities had enough places for all age groups.
Likewise in the east of England not one council said it had enough childcare for every age group.
Parents with children aged over 12 or with disabilities face the biggest gaps in provision, the survey suggests.
There was some respite for parents on price, with a week on a holiday play-scheme costing £121.12 this year, down from £123.49 last year, the survey found - but this masks wide variations.
Some publicly run schemes benefit from subsidies and free access to premises, but most schemes are run by private or voluntary groups which tend to charge more.
The average public sector scheme costs just over £100 a week for 50 hours of childcare, the researchers found, but the average private or voluntary scheme is about £123 a week.
Holiday play-scheme costs
Parents in the south east of England pay the most for holiday childcare, averaging £141.87 a week and this region also has some of the most expensive private play-schemes with parents paying up to £600 - almost five times the national average, the report found.
"We would like to see real commitment to increasing availability to meet demand, with a particular focus on deprived areas.
"Families should have a right to a childcare place, in line with a right to a school place," said Ms Margo.
England's Department for Education said it was pleased to see that the cost of holiday childcare is falling, "but we know that there is more to do".
"Councils must provide childcare for children up to age 14 for parents who are working, studying or training and we are helping schools to offer after-school and holiday clubs."
The Welsh government said it had provided £2.3m a year to local authorities since 2012 to provide childcare out of school hours and in the holidays.
This provision is focused on children from low income families and with special needs, said a spokeswoman.
A spokeswoman for the Scottish government said it had introduced a requirement on local authorities to offer more flexibility and choice on how funded childcare hours are offered.
"We are working with local government to further develop and expand their provision in this area, with the majority of local authorities now offering more flexibility to meet local demand."
Separately the NSPCC has urged parents to think carefully before leaving children home alone over the summer.