There are lots of decisions to make about the big day. One thing Kate doesn't want to worry about is how to get to the ceremony!
She'll be travelling in a Rolls-Royce, like this one, so that she arrives at Westminster Abbey in style.
The only problem is that the car she'll be using was badly damaged in the student protests before Christmas.
The windows were smashed and paint was thrown at the car. Experts are working hard to make sure the car is looking fit for a princess in time for the wedding.
And when they're married the couple will travel back to Buckingham Palace in this regal carriage.
It's been transporting royalty since 1902. And it's the same one that Prince William's dad, Prince Charles, used at his wedding back in 1981.
And if it rains then the Kate and William will travel in this closed-top carriage, called The Glass Coach.