450 entrants will take part in the 2014 event on 31st May.
Travelling across Cardiff thanks to free day tickets from sponsor Cardiff Bus, over 12 hours entrants are challenged to take 12 pictures on 12 given topics.
Topics are released in batches, at four-hour intervals, and will have to be captured and submitted in the correct order.
After the Photomarathon, all images are collated, printed and judged, before an overall winner, runner-up and 12 topic winners are announced.
All photos will then be displayed in a free public exhibition at the Old Library on the Hayes in Cardiff from 21st June.
The first UK Photomarathon was held in Cardiff in the summer of 2004 when 120 people took up the challenge. The event has grown year on year with almost 2000 people having taken up the creative challenge over the last decade, with over 23,000 images having been taken.
Founder Betina Skovbro, said: “When we launched the Photomarathon in 2004, my husband said it will never work! We thought we’d have 20 people maximum, so we were overwhelmed when 120 people signed up.
“The competition has grown every year since and I can’t believe we’re celebrating our 10th anniversary this year. Coming up with 12 really good ideas and responding to the challenge, is easier said than done, but I think people enjoy the creativity of the challenge, interpreting the topics in their own way, and capturing the capital city and its people through a lens.
“I can’t wait to see how entrants interpret this year’s topics.”
Gareth Stevens, business development manager at Cardiff Bus, said: “We’re happy to be once again supporting this year’s Photomarathon by offering free transport across the city for all entrants. It is a great day and we always look forward to seeing an abundance of photographers on our network. We wish all entrants the best of luck and congratulate organisers on a successful 10th anniversary event.”
This year’s Photomarathon is supported by Cardiff Bus, Cardiff Council, Wales Millennium Centre, CameraCentreUK, Cardiff Story, Arriva Trains Wales, Ffotogallery, Bob Books, Express Imaging and Waterloo Tea Gardens.
2013 winning photo – Elegant by Bruce McInnes