A police spokesman said he was found dead near the intersection of Seaton Rd, in Portobello, about 3.30pm.
At the time, the tide had started to come in, and the stony beach was only covered in shallow water.
Police initially had difficulty identifying the rider and were forced to make an appeal online to locate the man’s family.
They described him as being in his 70s, wearing a blue Eurobike top and a bright orange helmet.
Police eventually managed to track down a family member.
A Hato Hone St John ambulance and first response unit, and a Fire and Emergency New Zealand appliance also attended the scene.
The police spokesman said inquiries into the cause of the crash were ongoing and police were not ruling out a medical event.
"His cause of death will have to be determined by a postmortem."
He said the case might be referred to the coroner.
