Preschool teachers will and do change diapers when needed.
Some preschool students do wear diapers.
Although some preschool students are potty trained or partially potty trained it's normal for some preschool children to be wearing diapers and not potty trained.
Preschool teachers do change diapers if they have preschool students wearing diapers.
Some preschools will also have a teachers helper or teachers aide to help them with diaper changing which is what I used to do.
I used to work as a teachers helper in preschool and would help the teachers change the diapers of the preschool students and assist with potty training.
You can go to preschool wearing diapers as some preschool kids are only 3 and not ready to potty train.
I used to be a helper in a preschool and would change diapers on some preschool kids between the ages of 3 and 4 years old.
Some wore pull ups, some of them wore diapers and some wore underwear.
Some kids aren't ready to potty train until 3 and 1/2 and some kids aren't ready to potty train until 4 and near 5 years old.
Preschool kids don't have to be potty trained to attend preschool.
However preschool kids are usually expected to at least be trying to potty trained.
When I was helping in preschool we had around 5 preschool kids who were all boys who were not potty trained at all and were not ready to potty train.
So those preschool kids who were around 4 or almost 4 years old were in regular diapers and not pull ups.
I tried to assist with potty training them but they would not use the toilet so we just left it be.
My job was to change the diapers on the preschool kids who were not potty trained and it did not bother me.
The kid will potty train when they get there but they must be potty trained before going to Kindergarten the next year.
The majority of preschool kids are potty trained or at least partially potty trained and may need to wear pull ups but some preschool kids come into preschool wearing diapers.
There was also another kid in Kindergarten who was 5 years old and he wore diapers because he was too shy to use the toilet.
So his parents sent him to school in diapers.
We made it discrete that he could get his diaper changed in the nurses bathroom without anyone noticing.
He was potty trained and could use the toilet at home but he would not use the toilet at school or other public places so when he was not at home he would be wearing a diaper instead.