[1] To increase the possibility of qualification for top swimmers, the championships was made an Open tournament allowing competitors from countries outside Europe to compete.

[1] The Championship was staged at the Complexo Olimpico de Piscinas da Penteada, which also held the 2005 Multi-nations Youth Meet and the 2015 Winter International Masters Open.

Host nation (Portugal) Many competitors won multiple medals at the 2016 Championships.

Below is the list of countries who participated in the Championships and the requested number of athlete places for each.

As this was an Open Championship the countries are split between Europe and the Rest of the World.