Customs officers found objectionable content on his phone when he arrived at Auckland Airport in August last year.
Investigations showed he'd used chat apps to share files worldwide and discuss sexual abuse of children.
The 35-year-old Aucklander has been prosecuted for importing, exporting and distributing thousands of objectionable publications - and making one.
He has received four years 10 months in prison - and been placed on the child sex offender register.