The first Hector's dolphin calf has made its way into Akaroa Harbour, near Christchurch, to the excitement of tourism operators who run dolphin swimming and sightseeing tours.
Passengers on board a Black Cat Cruise vessel spotted the calf on Thursday.
Marketing manager Natasha Lombart says everyone on board was excited.
"Our passengers and crew were absolutely thrilled to spot the first newborn baby Hector's dolphin of the season.
The Hector dolphin calf swimming in Akaroa Harbour (Black Cat Cruises')
"The Hector's dolphin breeding season runs from late spring to early summer, so this young calf has appeared at the perfect time.
"[These dolphins are] one of the smallest and rarest marine dolphins in the world. Female dolphins only produce one calf every two to four years and do not start breeding until they are between seven and nine years old."
Cruise skipper Andrew Hopley said the passengers were treated to a rare sighting.
"We had a full swim boat with 12 local and international passengers, and they were all really excited to see a calf from such a rare species of dolphin thriving in its natural habitat.
"Our passengers are invited to observe the calves from the boat and take photographs, however we don't allow them to swim with them."
Black Cat Cruises carries more than 3.5 million passengers a year, and Ms Lombart says the team hopes to see more calves in the coming weeks.