Yes, a 99% C.I will be wider than a 95% C.I.
Just think of it in terms of a critical value from some probability distribution e.g. standard normal.
For example we could have XBar = 100 with a standard error of 10. Thus, the 95% C.I. would be
100 + - 1.96* 10.
The 99% C.I. would be
100 + - 2.58*10
obviously making it wider than the 95% C.I.