Make sure to bring formal Identification (ID) of some kind i.e. birth certificate, passport, drivers license. This allows confirmation of your date of birth and nationality. This is needed so that you can be formally assigned a World Cube Association¹ ID. You only need to bring identification to the first competition.

Lunch is not provided. (See question Do You Provide Lunch at Competitions?)

Aside from that, make sure you bring all the cubes you wish to compete with. Practice areas can be busy so to make best use of space we encourage cubers to bring their timers but not to bring their cubing mats with them (as they can take up a lot of space on tables.)