According to organisers, around 900 athletes will participate at the event in the Spanish city.

Britain has entered the most participants - 473 - across all of the races scheduled to be held over the weekend.

This amount surpasses the figure from the host nation as Spain have registered 392 athletes.

France have the third-highest representation with 33, while there will be 29 Irish duathletes also in attendance.

Germany have sent 12 athletes, one more than Italy and two more than Portugal.

Other countries present in the competition will be Austria, Belgium, Belarus, Denmark, the Netherlands, Poland, Romania, Slovenia and Switzerland.

Two athletes will run under the flag of the International Triathlon Union, according to organisers, as they are currently undergoing a switch in nationality.

"We are particularly excited by the fact that there is a significant presence of foreign triathlon athletes, as this event is especially important for Soria as an international showcase, and in this sense, the first step is taken," said Amancio del Castillo, President of the Castile-Leon Federation of Triathlon.

"Now, the only thing that is left is a good imprint to the visitors."

After the Opening Ceremony takes place today, races for elite men and women, as well as junior and under-23 athletes, come to the fore tomorrow.

A Para-duathlon event will also be staged.

On Sunday (April 30), the mass participation races for all age categories are scheduled.