For each edition, the Executive Committee of the Four Days of the Yser collaborates closely with the participating cities and municipalities. The participation, according to historical rules, of the municipality of Koksijde and the cities of Nieuwpoort, Poperinge, Diksmuide and Ieper is a certitude. They are represented in the Organizing Committee and each year the Four Days of the Yser passes on their territory. Their coats of arms are included in the logo of the Four Days.
It is obvious that the contacts and the cooperation with the other cities and municipalities where the 'Four Days' passes this year are also excellent.