I think there is a spelling error and it should be 'swimming stuff'. This means 'have you brought your swimsuit'.

I think I've got to agree with Yvonne, maybe it's a spelling error, because "swimming staff" really doesn't make much sense to me. Now how do I explain this? "Staff" means a group of people in a particular work area, like if you go to McDonald's, sometimes the employees/workers there are referred to as the "McDonald's Staff". The closest thing I can think of to the "Swimming staff" if it weren't a spelling error, would be lifeguards? Hope this helps :)

我沒聽過這些。應該是游泳隊或一個游泳池的人員。不過。。。staff另外一個意思是手杖，有沒有“游泳杖”？嘻嘻