A pod of 60 dolphins swimming and jumping out of the Piako River between Ngatea and Kerepehi made an impressive sight for some council workers on Monday.
Waikato Regional Council works supervisor Ian Sara spotted the dolphins upstream on the Piako River near Kerepehi about 7am as he was driving to a job.
Others spotted them from over bridges at Pipiroa and Ngatea.
Sara estimated the pod had about 60 dolphins heading upstream and travelling at "great pace" before returning around just past Ngatea and heading back to the Firth of Thames.
"I couldn't believe my eyes to be honest ... they were only 10m away from you and I was just parked on the side of the road.
The dolphins were diving in and out of the water.
"They were having a good old play."
Sera said the dolphins which included babies were up to 2.5 metres long and were travelling in groups of six with each group spaced about 50m apart from each other.
He estimated they were in the river for at least three hours before returning to the Firth at about 10.30am.
"They went up with the tide and then came back with the tide"
Hauraki District Council worker Peter Pakinga managed to capture a video of the pod as they swam under the bridge he was standing on near Ngatea.
On the video Pakinga can be heard commenting about the speed they were travelling and commenting on the large wake.
"That was a good pod. Even saw Flipper."
A boatie told the Herald she saw a small pod of dolphins while she was fishing on the Firth of Thames yesterday off Kaiaua just after midday and thought they must be the same ones.
"They were having a grand old time."