Adam Leyton and Chris Fletcher from Leeds want to complete the ultimate whistle-stop 1,600 mile tour of nine European capitals to raise cash for stillbirth and neonatal charity Sands.
They will start in London on Sunday and hope to be in Budapest just under 24-hours later.
They plan to travel through Paris, Brussels, Amsterdam, Berlin, Prague, Bratislava and Vienna
Father-of-three Mr Leyton already holds one Guinness World Record following a previous lightning tour of Europe.
He set out in May 2016 on an attempt to break the world record for the number of countries visited in 24-hours using only planes, trains and buses.
Mr Leyton, 41, started in Germany and journeyed through Luxembourg, France, Belgium, the Netherlands, Denmark, Sweden, Poland, the Czech Republic, Slovakia, Hungary and Austria.
He beat the existing 1993 world record of 11 countries visited in 24 hours when he made it 12 with just minutes to spare.
He ran the final 4km and crossed from Hungary to Austria to finish in 23 hours and 52 minutes.
Mr Leyton, formerly of Horsforth but now of Edinburgh, said: “We need to travel inland as far as the capital itself and visit a central square, government building or major train or bus station.
“With Brexit around the corner we thought it was the perfect time to see as much of Europe as we could, in a day.”
Mr Fletcher, 38, of Burley, Leeds, said: “This time together, we’re aiming for the capitals”.
As they make their way around the continent the pair, who are friends and co-owners of marketing agency CEE Digital, will be raising money for Sands, the stillbirth and neonatal death charity.
Sands offers support to anyone who has been affected by the death of a baby.
Eight years ago, Mr Leyton’s sister Gemma lost her baby daughter Tilly Rose just five-days before she was due to be born.
Mr Leyton said: “The support Sands gave my sister and her family was incredible.”
Follow their progress at www.9in24.co.uk or make a donation to Sands at justgiving.com/9in24