A 31-year-old man from Hobart is accused of almost 100 child sexual offences over a period of five years.
He was arrested on Monday by Tasmania Police and Australian Federal Police officers following a "significant" investigation.
He was charged with 79 counts of using a carriage service to engage in sexual activity with a person under 16.
He also faces eight counts of using a carriage service to procure a person under 16 years of age and six counts of causing the transmission of child abuse material.
The man, who appeared in Hobart Magistrates Court on Monday and was remanded in custody, is also accused of using a carriage service to solicit child abuse material and possessing child exploitation material.
1800 RESPECT (1800 737 732)
National Sexual Abuse and Redress Support Service 1800 211 028