Department of Conservation (Doc) coastal Otago biodiversity ranger Jim Fyfe said the bottlenose dolphin was seen "bumping around" in the Blueskin Bay inlet yesterday morning.
Onlookers on the side of Waikouaiti-Waitati Rd (State Highway1) reported it stranded in the outgoing tide about noon.
"We think it was just geographically embarrassed.
"It had come into the inlet and been caught out by the tide.
"People responded fairly quickly and promptly, and there were enough skilled and knowledgeable people around ... to start walking the dolphin back towards the entrance on a tarpaulin."
Both Doc and the Warrington Surf Life Saving Club were notified and turned up at Doctors Point with a whale rescue pontoon and inflatable rescue boat (IRB), Mr Fyfe said.
They were then able to take some people in wetsuits and flippers over to the dolphin, place it on the pontoon and float it out to the bay entrance to be released.
The dolphin had needed "a bit of coaxing" and use of the IRB to discourage it from swimming back into the inlet.
Dive Otago also pitched in with the rescue effort.
Mr Fyfe said those who had walked it down the channel got it to a "perfect place" for when the pontoon arrived to get it into deeper water.
Blueskin Bay had a history with stranded dolphins, and they were not unusual to see.
"It’s a really, really shallow inlet and the occasional dolphin comes swimming in and sees a few fish around and thinks, ‘oh, this is a good lark’, and gets up into the inlet.
"Often they’re ... a bit naive about the water going up and down by a couple of metres and quite quickly get disoriented and might be caught out by the tide.
"So it seems like that’s what’s happened in this case. It’s just probably a little bit embarrassed now that it sort of got itself into this situation in the first place."
Members of the public who see a stranded marine mammal should call Doc for advice before taking action.
The actions of first responders in this situation was a "textbook response", he said.
• For conservation emergencies, call 0800 DOC HOT (0800362-468)
