2018    
1-3 August WRE Falco Cup, Lithuania. PreO WRE on Day 3. Bulletin 2 (final details) here
4-11 August   World TrailO Championships, Latvia. Bulletin 2 here
16-19 August   Hungaria Cup, Tapolca, Hungary. 4 days of PreO, can be combined with FootO events. Info here
22 August   Cerkno Cup, Slovenia. PreO (combined with FootO event). Information here
25 or 26 August   White Rose Weekend PreO, Duncombe Park, Helmsley. Information here
2 September BO Ranking Event East Harptree Woods, nr. Stockhill (after British Middle Champs.)
22-23 September ECTO ECTO 7 & 8: Denmark (Silkeborg, Jutland). 2 x PreO. Information here
6-7 October ECTO+WRE ECTO 9 & 10: Czech Republic. PreO WRE + TempO WRE. Same venue as FootO World Cup
26-31 December   Gran Canaria O-meeting, includes 1 day of TrailO. Information here
     
2019    
23-29 June   World TrailO Championships, Idanha-a-Nova, Portugal. Bulletin 1 here
     
2020    
early November   World TrailO Championships, Hong Kong

WRE = IOF World Ranking Event

ECTO = European Cup in TrailO

The following events usually have one or more TrailO competitions along with FootO competitions:

Portugal O-meet, February (PreO)

Lipica Open, Slovenia (PreO)

JK, Easter weekend (TempO + PreO)

British Orienteering Championships and British TrailO Championships (PreO) on the same weekend, same venue

Wawel Cup, Poland, July (PreO)

Swedish O-Ringen, July (5 x PreO)

Scottish 6-Days, July-August (PreO)

Hungaria Cup, August (4 x PreO)

Cerkno Cup, Slovenia, August (PreO)

White Rose Weekend, August (PreO)