The interisland ferry Aratere is crossing Cook Strait for the first time since breaking down last year.
A propeller fell off the ship during a crossing from Wellington to Picton and it had to be repaired in Singapore.
The ferry left Wellington at 5pm on Thursday on a test trip to Picton and back.
Later this week, the Aratere is scheduled to begin freight-only sailings on a reduced timetable; it will start carrying passengers on 14 July.