Being up here I have the 3 disciplines Game, Sea and Coarse. With coarse and game on the same rivers.
Then there's the Esthwaite Water Kayak 3 predator species comp all on the fly.
To answer your question it has to be Coarse, Game and Sea in a day. To mix it up depending on where you live or where the challenge is set could be fly on a river, coarse on a lake and then to the coast for the sea. But up here it would be coarse on a lake fly on a river then onto the sea.
For those who want to do a single discipline :-
Coarse is river, lake and canal.
Sea could be Beach, Pier and rock or boat/kayak (if you own one).
Fly fishing is stream/brook,river and lake.
You could change lake to reservoir but that's depending on where you live.