Figures obtained by the Express & Star showed councils had allowed more than 200 children to start school later than they would have been expected to.
Children usually start primary school during the academic year when they will turn five. But dozens have parents have challenged the accepted norm since 2016.
Data showed that some councils were more willing than others to accept requests for a delay.
Staffordshire County Council said it had accepted all 112 requests to delay a child starting school over the last five years.
Walsall Council, on the other hand, refused 21 out of 69 requests, accepting the other 48. The authority said where applications were refused it was "not in the best interests of the child".
Dudley Council said it agreed to at least 53 requests but didn't confirm how many it had refused, adding all decisions taken were in the best interests of the child.
Wolverhampton Council received 79 requests, so far accepting 51 and refusing eight. There was a large increase in requests during the pandemic, the figures showed. Sandwell Council did not respond to the request for information.
Children born between April 1 and August 31 - known as summer-born - don’t legally have to start school until the September after their fifth birthday but there is no guaranteed access to education if children don't attend in their age group.
Parents in some parts of the country have faced difficulties in trying to delay their children starting school.
Staffordshire mother Rosie Dutton successfully delayed her daughter Olivia's start to school and raises awareness of the issue as a 'summer-born' campaigner.
She felt her daughter would be better off having another year in nursery before starting school.
"Most parents aren't aware of it. Even some schools and teachers aren't aware of it," the 36-year-old from Tamworth said.
"It's a massive postcode lottery. Five local authorities automatically agree to it but others are quite against it.
"I just felt the environment with a higher adult to child ratio than school where she could go outside if she wanted to would really help her personal development."