Active transport (AT) contributes to human and environmental health but is low and declining in New Zealand (NZ) children and youth. Quality evidence is necessary to inform and evaluate interventions, identify inequities, and understand trends. NZ has participated in the Global Physical Activity (PA) Matrix since 2014. This collaboration uses a harmonised process to develop national Report Cards including “grades” for PA behaviours, including AT. The purpose of this article is: (1) to detail the development of NZ’s 2018 PA Report Card, focusing on AT; (2) to examine AT trends across the Report Cards (2014/2016/2018); and (3) to consider implications of methodological approaches and available data sources for monitoring and promoting AT.