The dead juvenile sperm whale was first sighted at the weekend near Mayor Island and had drifted towards the beach near Harrison's Cut in Papamoa.
It finally washed ashore between the Cut and Papamoa Surf Life Saving Club about 5.30pm yesterday, attracting crowds of people and young children.
Vanessa Wilson watched as her children played in the water with the carcass.
The father of the children had spotted the whale offshore and swam out to it, believing it might have been sick.
She said he hopped on its back and guided it in to shore but realised by the stench it had already died.
Security guarded the carcass overnight to protect the whale's valuable jawbone. A burial was expected to take place in the sand dunes this morning, with iwi and Department of Conservation staff present.
Earlier yesterday, emergency services rushed to Harrisons Cut where a yacht was believed to have capsized only to find it was the whale.
Papamoa surf lifeguards were sent out to investigate the report and instead found a smelly, rotting whale.
"It's big and white. All the skin's peeled off," lifeguard Matt Strange said.
A large sheen of oil could be seen on the water around it.
Department of Conservation project manager of biodiversity Brad Angus said they first received reports of the whale carcass on Thursday, floating north of Mayor Island (Tuhua).
"Then it was reported south of Tuhua over the weekend and there it is," Mr Angus said, gesturing to the carcass.
Fish spotter Brian Decke saw the whale drifting a considerable distance between Mayor Island and Motiti Island at the weekend.
"I came across the whale on Saturday, it was east of Mayor Island.
"On Sunday it was east of Pudney Rock which is about six to seven miles west of Motiti Island.
"It had drifted about 12 miles overnight.
"It was fairly big, I wouldn't want to run into that on a boat. It was floating so it would be a navigational hazard at the moment but when it decays a bit more it may sink."
The last time Mr Decke saw a sperm whale was at Great Barrier Island and he said he had never seen one around Tauranga before.
"I've been doing this job for 25 years and haven't seen one this close to Tauranga before."
Bay of Plenty Regional Council Tauranga harbourmaster Jennifer Roberts said the council was notified of the dead whale by DoC during the weekend.
She said the reported position of the whale was 10 nautical miles off the coast, which meant most boaties weren't affected.
"However, as the whale was reportedly floating towards the shipping channel, we notified the port's customer service centre so they could alert shipping.
"The Tauranga Coastguard was also notified and they then broadcast alerts out to boaties."
