The competitions took place from October 7th to 13th.
Each National Olympic Committee (NOC) was allowed to have a maximum of two teams per gender in one of the team sports (futsal, beach handball, hockey, and rugby 7). The host nation was allowed to provide a team in each team sport.
Originally, in addition to the host from Argentina, the hosts from Mauritius (before Togo and South Africa), for the starting place of Oceania, Australia (before New Zealand), for the two starting places of the Americas Venezuela and Australia qualified for a starting place from Africa at the Beach Handball Junior World Championships in Mauritius in 2017 Paraguay, for the two starting places in Asia Taiwan (Chinese Taipei) and Thailand (before Pakistan). Spain, Italy and Russia (ahead of Portugal) qualified for the three starting positions in Europe.
Italy and Russia had also qualified for the boys' futsal tournament. Italy decided to take the starting place in beach handball, Russia in futsal. Thus Portugal moved up as the best European team in the Junior World Championship. Australia decided to take part in the hockey tournament. Thus New Zealand would have moved up, but also decided against it, so that the starting place Oceania remained vacant. The last two free places were given to countries that had no qualifying places in any other team sport, Uruguay and Croatia.
Preliminary round
The preliminary round matches were played from October 8th to 13th.
The hosts from Argentina were automatically qualified. The other starting places were allocated based on the placements at the 2017 Junior World Championships in Mauritius. Venezuela and Paraguay qualified for the two starting positions of the Americas (Brazil did not compete), for the starting positions of Asia Thailand and China (ahead of Taiwan and Hong Kong), the hosts from Mauritius got the African starting positions (Togo's team did not compete). American Samoa won the starting position of Oceania (ahead of Australia), Hungary, the Netherlands and Portugal (ahead of Spain and Croatia) qualified for the three starting positions in Europe.
Chinese Taipei (Taiwan) and China had also qualified for the girls' hockey tournament and Portugal for the futsal tournament . Chinese Taipei decided to take part in the beach handball tournament, Portugal for futsal, China for hockey. Thailand did not take advantage of the starting place either, but instead competed in beach volleyball. In return, Hong Kong moved up, so that both starting positions in Asia were filled by newcomers. The first European successors from Spain also decided to take part in beach volleyball, so Croatia moved up into the field. The remaining two free places were given to nations without qualification places in other sports, Russia and Turkey.
Preliminary round
The preliminary round matches were played from October 8th to 13th.