My 2.5 year old snores loudly and breathes thru mouth when sleeping? is this normal or reason for concern?

Concern: Generally this does not happen at this age. Although not an emergency, you should see your pediatrician for the cause.Usual causes include allergies and / or some sort of nasal obstruction.

Reason for concern: It is not normal for a 2 year old to snore loudly. It is a sign of a resticted airway. Please talk to your pediatrician, who may recomment an ENT to evaluate the airway, tonsils, etc. Proper airflow is important for growth and development.