Surapong Ariyamongkol of the The Athletic Association of Thailand, which oversees athletic events in the country, accredited the route change to a "technical error."
He told The Guardian that the race officials responsible for pointing runners in the right direction inadvertently directed them to make a U-turn at the wrong place. This error "added more than 3km [1.8 miles] to each lap, therefore more than 6km were added to the whole half-marathon."
However, these "bonus miles" were freebies most of the runners were not too thrilled to receive. As people tend to do these days, they have taken to social media to voice their distress.
@Supercords@AsCorrespondent there were quite a few ppl in the medical tent. Luckily I'm just very sore and not injured, esp with my spine.
THAILAND - JUNE 15: Kamala Beach, Phuket, Thailand. (Photo by DeAgostini/Getty Images)
[UNVERIFIED CONTENT] Phuket @ Thailand
KO SURIN, THAILAND - 2014/03/02: A tourist climbs one of the boulders on a beach in Mu Koh Surin National Park. (Photo by Taylor Weidman/LightRocket via Getty Images)
KO SURIN, THAILAND - 2014/03/02: Beachfront camping in Mu Koh Surin National Park. (Photo by Taylor Weidman/LightRocket via Getty Images)
Silhouetted tourists walk past fishing boats on Railay beach in Krabi, Thailand, on Saturday, Jan.18, 2014. The Bank of Thailand will probably reduce its key interest rate by 25 basis points, or 0.25 percentage point, to 2 percent today, according to the median of 21 economists' estimates compiled by Bloomberg. Photographer: Brent Lewin/Bloomberg via Getty Images
KRABI, THAILAND - 2013/11/10: Thai Speedboats closeup at Koh Chuek near Koh Lanta. (Photo by Olaf Protze/LightRocket via Getty Images)
KRABI, THAILAND - 2013/11/06: Wild Macaque at Ao Nang Beach. (Photo by Olaf Protze/LightRocket via Getty Images)
KRABI, THAILAND - 2013/11/07: Scenic sunset at Klong Nin Beach at Koh Lanta Island. (Photo by Olaf Protze/LightRocket via Getty Images)
Thailand, Phuket Province, Phuket, Big Buddha Temple. Large seated golden Buddha figure in temple courtyard. (Photo by: Eye Ubiquitous/UIG via Getty Images)
KRABI, THAILAND - 2013/11/06: Tourists at Ao Nang Beach play with Monkeys. (Photo by Olaf Protze/LightRocket via Getty Images)
KRABI, THAILAND - 2013/11/06: Tourist Boat full of tourists arriving at Ao Nang Beach. (Photo by Olaf Protze/LightRocket via Getty Images)
Thailand, Koh Samui, Choeng Mon Bay, Samui Peninsula Resort Massage Spa House overlooking beach (Photo by: Eye Ubiquitous/UIG via Getty Images)
To go with AFP Story Thailand-lifestyle-tourism-crime,FEATURE by Daniel Rook
This picture taken on February 14, 2013 shows a tourist on Patong beach in Phuket, southern Thailand. From jet ski scams to robbery, assault and even police extortion, for the millions of tourists who flock to Thailand each year the kingdom does not always live up to its reputation as the 'Land of Smiles'. Now following a flurry of complaints, governments are urging the country to do more to protect the safety of the record numbers of foreign visitors. AFP PHOTO / Nicolas ASFOURI (Photo credit should read NICOLAS ASFOURI/AFP/Getty Images)
HUA HIN, THAILAND - 2012/12/28: Dragons, Gulf of Thailand at Khao Takiab towards the southern end of Hua Hin beach which is famous for its 20 meter tall Buddha. Meaning literally 'chopstick hill' Khao Takiab is at the southern end of Hua Hin beach famous for its 20 meter tall Buddha statue. There is a trail to the top of the mountain, where visitors can clearly admire the scenery of the Gulf of Thailand and Hua Hin city. (Photo by John S Lander/LightRocket via Getty Images)
KOH SAMUI, THAILAND - OCTOBER 17, 2012: In the early morning, view on Lazy Days Samui Beach Resort at Lamai Beach on Koh Samui. (Photo by Adrian Streun/ASAblanca via Getty Images)
PHUKET, THAILAND - NOVEMBER 22: Mark Kok Loong Leong of Singapore competes in the Semi Final of the Men's Team Slalom Water Ski during the 2014 Asian Beach Games at Bangneow Dam on November 22, 2014 in Phuket, Thailand. (Photo by Quinn Rooney/Getty Images)
Thailand, Phuket Province, Wat Chalong, Highly decorative Buddhist temple exterior (Photo by: Eye Ubiquitous/UIG via Getty Images)