Uli Kilian, 34, works at a 3-D animation studio in Soho and is the self-proclaimed "Rubik's Runner" who says he hopes to raise thousands of dollars for charity, the online newspaper, thisislocallondon.co.uk reported.
The London Marathon is April 17.
Kilian first set himself to the task of running the marathon while solving the cubes in 2009 when his father came down with prostate cancer and Kilian says the money he raises will go to Prostate UK.
One of the biggest difficulties is the weight, he said.
"It's a bit of a logistical problem," Kilian said. "A hundred cubes would be too heavy to carry in a rucksack and support runners were difficult because we would have to secure a place for all of them, so I'll have keepers who will hand me the cubes along the circuit."
The multitasking runner will have friends and family along the circuit to hand him 20 unsolved cubes at a time and who will grab up the solved puzzles. He'll also have a small video camera attached to his body to show he solved the cubes while running.
An official from Guinness will be at the finish line to collect the cubes.