Most nations celebrate Father's day on the third Sunday in June (such as U.S.A., U.K. and Canada), although some countries also celebrate this day at other times of the year. For a full list of dates, please see this guide.
This page has two prayers - one for young children and toddlers and another for older children to say or write:-
A Prayer for My Daddy
(a short Father's Day prayer suitable for young children to write or say about their dad)
Thank you for my daddy.
He looks after me, plays with me,
Listens to me and makes me laugh.
He works very hard and sometimes he gets tired.
Please give him good sleep.
Help him to rest.
Give him happy times and lots of hugs and kisses.
(a Father's Day prayer for young children from www.lords-prayer-words.com)