The 71-year-old who died after he crashed his car into a lampost was a keen adventurer who'd trekked to Everest Base Camp.
In a moving tribute to John Robertson, his long-time friend and partner Maggie Cornelius said his death had left his friends and family "in bewilderment and sadness".
Mr Robertson, from Plasmarl, Swansea, was killed on Bank Holiday Monday afternoon after the single-vehicle crash on Clasemont Road, Morriston.
Ms Cornelius said the pensioner, who worked as an intensive care nurse and volunteered with a number of organisations, would be "sorely missed" by her as well as Mr Robertson's brother David, sister-in-law Jill, nephew Alex and wife Amber and great nephews Miles and James, who live in the USA.
Ms Cornelius, who's family live in Wales and are also grieving, said: "John had many interests and in recent years after retiring as a nurse in ITU in Morriston hospital, he volunteered with the RSPB, the National Trust in Aberdulais and the Glamorgan Gwent Archaeological Trust (GGATT) in Swansea.
"He spent many years in the Scouts travelling, walking and climbing all over the world - including Mera Peak and Everest Base Camp. His health this year caused him to have a stay in hospital but he was soon able to restart his activities.
"The shock of his sudden death has left us all in bewilderment and sadness."
Mr Robertson was declared deceased at the scene of the crash and the road was closed until 2am on August 31.
South Wales Police said officers are continuing to appeal for any witnesses who many have been in the area at the time of the crash on Monday afternoon, at around 2.19pm. Anyone who knows anything more about the collision on August 30 or who might have dash-cam footage that could assist with the investigation should contact the force quoting reference 2100305521.
You can submit information online, via a private message on Facebook or Twitter, emailing SWP101@south-wales.police.uk or phoning 101.
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