To describe healthcare pathways for mild traumatic brain injury (mTBI) patients in New Zealand and identify areas for improvement. A data science methodology was applied to mTBI ACC claims (children and adults) between 1 September 2016 and 1 September 2018, and payment and purchase order data until 1 September 2020. Frequency, median and interquartile ranges were used to describe the pathway. Of the 55,494 claims and 63,642 referrals, >99% were accepted by ACC. Claim processing took more than a week for 7% (3,647) of claims and referral processing took more than three days for 33% (21,139) of referrals. One in four (25%) cases referred to a concussion clinic took >2 months to receive the service due to administrative delays. Of all patients, 36% (20,413) received more than the initial appointment, and their median time in the pathway was 49 days (IQR, 12-185). TBI diagnostic codes were not added at initial appointment in 6% (3,382) of cases. Administrative claim and referral processes resulted in minimal delays in the pathway for most patients. However, the volume of claims meant delays affected thousands of New Zealanders every year. Pathways could be improved by facilitating mTBI diagnosis, improving follow-up rates and reducing unnecessary administrative processes.