Until the start


What is K3 ULTRA

K3 ULTRA – GOLD BORDER RACE is the first ultramarathon whose routes cover Bulgaria’s borderline part of the Rhodopes.

The event takes place at the end of September – the most colourful and picturesque month of autumn.

The finishing line of the K3 ULTRA – GOLD BORDER RACE is in the country’s southernmost and magnetic town – Zlatograd.

The ultramarathon offers several distances.

The marathon routes alternate between breathtaking views and adrenaline-pumping sections.

These include a climb to the medieval Kechi Kaya Fortress and the chapels of St. Athanasius, St. Nedelya, St. Ekaterina and other historical and natural attractions.

The routes also reveal 360-degree views of the magnificence of the Rhodopes in some places, and in others – the runners will have the opportunity to enjoy a panorama of both Bulgaria and neighbouring Greece.

Map of the K3 ULTRA GBR Ultramarathon

View K3 ULTRA GBR trails

Get ready for an exciting experience

The trails of the K3 ULTRA GBR






Why participate in K3 ULTRA

Gold Border race – Experience your golden adventure

What does the K3 ULTRA GBR give you?

  • A variety of distances to suit your physical fitness – 13K, 23K, 43K, 63K, and 85K;
    mountain trails running along the Bulgarian-Greek border and revealing 360-degree panoramic views of the Rhodopes;
  • Piled aid stations, where traditional Rhodope specialities, prepared by the hands of local residents, will await you;
  • Participation in our green cause, in which we allocate no less than 20% of entry fees to purchase trees, because we love the mountains!

UTMB® INDEX RACE – Get a chance to qualify for a UTMB World Series Marathon

K3 ULTRA is a qualifying competition for UTMB. After the finish of the ultramarathon, participants receive a Performance Index and can use it to qualify for other races of the UTMB. This gives them a chance to become part of one of the most exciting races on a global scale, to go through unique routes and destinations and to experience the emotion together with other skilled competitors from different parts of the world.

Emotion at every step

The incredible and breathtaking views are combined with many emotional experiences and surprises along the routes. The feeling of freedom, timelessness and harmony is part of your journey on the K3 ULTRA trails.

K3 Ultra GBR – the favourite ultramarathon of the little ones

Every year the youngest sports enthusiasts take part in the K3 Ultra GBR Children’s Marathon. Created for a non-profit purpose only, it nurtures love for the mountains and for sports from an early age. It also helps stimulate young people towards a healthy lifestyle and motivates them to take care of their physical shape and Nature. The 5-kilometre trail starts from the town of Zlatograd, continues to the St. Athanasius Chapel and finishes again in Zlatograd.

Great things happen when people meet mountains!

More than an ultramarathon

K3 ULTRA gives you the opportunity not only to challenge yourself, but also to be a participant in the events that are organised alongside the ultramarathon : a Patatnik Party, musical programmes and cultural events, our annual Tree Planting Green Cause and more. They bring good mood, good moments and become unforgettable memories.

The big medal

By winning the medal from our gold adventure, you take another step towards collecting the Grand Slam. K3 ULTRA GBR, together with Tryavna Ultra, Pirin Ultra and Tarnovo Ultra joined together in the large-scale project to showcase the beauty of the Bulgarian mountains.

The green history of K3 ULTRA

Our Green Cause

K3 ULTRA is an experience shared with nature and its magnificence. Many participants, volunteers, sponsors, and partners of the ultramarathon will have the opportunity to plant a tree before the event is closed. This is our contribution to preserving nature, renovating the forests of the Rhodopes and a piece of gratitude in return for what nature gives us.

No less than 20% of the funds collected from the entry fees in K3 ULTRA GBR each year are used for buying and planting trees along the streets and the surroundings of Zlatograd. Participate personally in planting the trees and in the Green history of K3 ULTRA.


The K3 ULTRA GBR T-shirt is made of high quality breathable fabric to be a loyal and faithful ally of the runners in the mountain. The design of the T-shirt successfully conveys and complements the overall experience of K3 ULTRA.

*The T-shirt of the event is NOT included in the starter pack, but it can be ordered additionally on registration.

What is included in the K3 ULTRA entry fee

What you get

Starter pack

The starter pack for each contestant includes a starter number, gifts from the sponsors and partners of the competition as well as a special surprise prepared by the organisers.

Perfect event organisation

K3 ULTRA participants will have carefully placed markings, cleared and safe trails with minimal asphalt sections, electronic reporting of the results, information on hotel accommodation, tent and camper site. Professional photo footage.

ITRA Certification and UTMB Index

Ability to qualify for the UTMB® Index and for ITRA Certification.

Medical assistance

The safety of the participants in the ultramarathon is ensured by mountain insurance included in the entry fee and the availability of medical assistance during the entire event.

Food and drinks

The aid stations at the ultramarathon will be stocked with water, hot and refreshments. Special food is also provided – fruits, vegetables, Rhodope specialities, as well as supplements.

Unforgettable moments

Amazing views, emotional experience, fabulous Rhodopes and new friendships. All participants who cross the finishing line of K3 ULTRA will receive a medal - part of the Grand Slam, uniting the leading ultramarathons in Bulgaria.

Register for one of the most emotional ultramarathons in Bulgaria


Don’t miss it!

Early bird registrations have started




What it is like to be part of K3 ULTRA

General sponsor

Sponsors and partners