The South Perth resident will cycle more than 300km over two days from Perth to Margaret River as part of the 2013 ProState Active.
The purpose of the event is to raise awareness of prostate cancer and funds for the Prostate Cancer Foundation of Australia.
Mr Williamson said early detection and awareness of the cancer was an important issue.
In 2008, at the age of 58, Mr Williamson was diagnosed with a malignant melanoma, which he said made him think there may have been something more wrong.
‘So I went for a few tests and they found I had reasonably advanced prostate cancer,’ he said.
He explained that his case was beyond surgery and he opted for a non-surgical procedure.
He went through one year of hormone drugs, then had brachytherapy and then seven weeks of external radiation.
‘Being on the hormone treatment is quite a traumatic thing,’ he said. ‘I became a bit chubby and lost a lot of muscle tone, my body hair fell out and I went through a whole bunch of other physical changes that were not very nice.’
Now 62 and in remission, Mr Williamson said he felt ‘fantastic’ to be the oldest person on the team.
‘I am training with guys in their 30s and 40s, and managing to keep up quite well, so I am quite pleased,’ he said.