Police were called to the scene, on Chao Fa East Rd, about 350m south of Dowroong Wittaya School, at about 11:50am.
Emergency responders arrived to find the woman, named by police as ‘Ms Kwanjai’, unconscious in the middle of the road with a severe head injury.
Despite efforts to resuscitate her through CPR, she was pronounced dead at Vachira Phuket Hospital.
According to police, Ms Kwanjai was riding pillion on a red Honda Wave driven by her husband.
The couple had just left the Wichit Subdistrict Health Promoting Hospital, where Ms Kwanjai had undergone dialysis.
As they made their way home to Thalang District, light rain made the road slippery. Her husband lost control of the motorbike, causing Ms Kwanjai to fall and strike her head on the road.
It was not reported whether Ms Kwanjai was wearing a helmet at the time of the accident.
Local residents told reporters that at least eight other motorcycles also slipped and fell in the same area during the rain.
The road is notoriously hazardous during wet conditions and local residents urged authorities to take immediate action to prevent further accidents and loss of life.
Local residents today also complained about calls to the Wichit Police Station main number 076-355073 going unanswered. Finally they were able to contact police and emergency services.
Faster response times would help to prevent more lives lost, local residents said.