In New Zealand, barriers to the migration of shortfin eels (Anguilla australis), including those associated with hydropower, are of increasing concern to water resource managers. Understanding eel migratory behaviour around such infrastructure is essential to quantify the impact and develop passage solutions. Downstream migrating adult silver eel were caught, surgically implanted with an acoustic transmitter and released in the Wairua River, New Zealand, at two sites (33-km upstream of the Wairua Power Station diversion weir (n = 12) and in the power station canal 2.2-km upstream of the intake (n = 13)). Tagged eels were detected on 19 acoustic receivers strategically located around the catchment, including arrays of multiple receivers in the forebay of both the diversion weir and the power station to quantify escapement, route choice, delays experienced and areas occupied at structures. Three of 11 eels that reached the weir from the upper release site passed through a gate at the diversion weir, hence avoiding the power station, with the remaining eight and all 13 released in the power station canal (n = 21) entering the power station forebay. Ten eels that entered the power station forebay (48%) passed over the spillway after experiencing delays of between 12 to 46 days. The other 11 tagged eels were either impinged on the intake screen or entrained in hydropower turbines. The influence of power station operation and spill prior to and during impingement and passage will be presented, including conditions experienced when eels passed the diversion weir, speed of eels migrating through an unobstructed reach, behaviour upstream of the intake and onward migration. Recommendations for maximising escapement from the Wairua River will be discussed based on knowledge of tracked eels; information that is transferable to rivers with similar hydropower schemes.