Here are the dates and locations for upcoming IAU World Championships as well as team application deadlines:

IAU 50km World Championships 2016 in Doha Qatar 11th November –
Application closing date 13th June after Gold Coast 100 km on 11th June

IAU 100km World Championships 2016 in Spain 26th November –
Application closing date 20th June after Sri Chinmoy 24hr/12hr on 19th June

2016 Trail World Championships
in Portugal 29th October –
Application closing date 30th May after North Face 100km

2017 IAU 24H World Championships Belfast 1st/2nd July –
Application closing date 1st December after all 24hr race in Australia and New Zealand