If you want to keep up with what's happening in the big wild world of memory competitions, you really need to be reading Johann Randall Abrina's blog! Just to look at that summary of all the competitions so far this year fills an old-timer like me with a warm glow of satisfaction - when I started out, there were three or four competitions a year, at the very most, in the whole world! Now even a backwater of modern memory like the British Isles has that many itself, and the cool countries are all running their own competitions all over the place too!
I think the 'big' competition before the world championships is still the German Memory Open, buried though it is in such a busy summer calendar, but don't forget the UK Memory Championship a month later (that link isn't a website of its own, just a note that it's going to happen, but it really is definitely going to happen, and worth going to!)
Or take your pick from any other event on the calendar - that's Mnemotechnics.org, which keeps a good and accurate list of what's happening. There will be a World Memory Championship too, most likely, but they're adopting the successful technique from last year of not revealing any details and then having to retract it when they change. So I don't need to warn anyone not to book their plane tickets, unless they're the kind of person who just guesses the date and location of a memory championship, buys a first class ticket and hopes for the best. And if they are, they probably wouldn't listen to me.