"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."