Crews were called to the scene at 11:46 p.m. Monday at the Tredyffrin Township Mazie B. Hall Park "Tot Lot" on the 1000 block of Upper Gulph Road in Wayne, Pennsylvania.
The play area was destroyed with an estimated loss of more than $60,000.
Authorities had initially deemed the fire as suspicious. However, they later determined the cause to be accidental.
Officials have not released any details on what led to their conclusion.