The Duke of Rothesay, as he is known when in Scotland, attended the event in his role as chieftain.
He watched traditional Highland games competitions such as the three-legged and egg and spoon races. He then presented a trophy to the winning tug o'war team.
About 400 people attended the games on Saturday.
It is usually staged in a field nearby to Castle Mey, the late Queen Mother's Scottish home in Caithness, but was instead held at a field in John O'Groats due to the usual setting being water-logged.
Prince Charles drove to the event himself and was wearing traditional Scottish dress.
He appeared to be in high spirits whilst watching a mock horse dressage with participants prancing around on a wooden hobby-horses.

Pupils at Pingle School, Swadlincote, were asked to send naked images to the messaging site ooVoo.
Derbyshire Police said it was "investigating the sharing of indecent images" via text message, social media, or tablet and phone apps.
The force said it was unclear who made the requests. The school said warnings were sent to parents and other schools.
Simon Waller, assistant head at the school, said: "It came to light after one of our mentors had seen a text message and was quite suspicious.
"It started off quite low key but the more we dug, we uncovered quite a big problem.
"We've got a really rigid e-safety programme. Clearly some of the messages aren't getting through, so we have got extra measures in place."
He said police officers were coming in to deliver assemblies on online safety to all year groups. Pupils are aged from 11 to 18 years old.
A Derbyshire Police spokesperson said the investigation was in an early stage and it was not yet known whether requests were sent by a lone online predator.
Police have urged parents to be vigilant and monitor their child's online activity.
A spokesman for ooVoo said the issue was a problem for the social media industry and the site aimed to provide users with a "safe and private experience".
He said: "We take these issues very seriously and have a chief privacy officer who roots out and deletes any accounts which may place children or any ooVoo users at risk.
"The reported behaviours are offensive, illegal and when identified as such will be immediately reported to the proper authorities."

Eighteen people were arrested during the four-day operation and 63 vehicles were seized.
Forty-two of the vehicles had no insurance and/or licence.
A further 21 had no Vehicle Excise Licence, the Hampshire and Thames Valley operation discovered.
Hampshire Constabulary and Thames Valley Police said the joint operation earlier this month aimed to make the roads safer for people living and working in the region.
The "large quantity" of the substance believed to be cocaine was discovered in a car in the Iver and Denham area, officers said.
Other items seized included a stolen digger worth £12,000.
The lorry driver asleep in his cab was in a vehicle "piggy-backing" another vehicle in Portsmouth.
Both drivers were given fines totalling £1,000.
Prince Charles has umpired a tug o'war competition during a visit to the Mey Highland Games.
[NEXT_CONCEPT]
Police are investigating after pupils at a Derbyshire school were encouraged to post explicit images online.
[NEXT_CONCEPT]
A lorry driver asleep at the wheel and a car thought to be carrying £100,000 of cocaine were among the discoveries made during a police crackdown on motoring offences.