There is basically no restriction. However, you should keep in mind that storage space in the cabins is limited and that there are no storage rooms on the ships. That’s why it’s best to avoid suit cases (especially hard-cover suitcases are completely out of place here) and bring a duffel or flexible travel bag instead. You should also bear in mind that casual clothing is required on our trips and that you certainly don’t need to take evening dresses with you.