Yes, the vast majority of people can and do build a tolerance to sea sickness through a process known as habituation. This is colloquially referred to as "getting your sea legs." When you are exposed to the constant motion of a ship, your brain eventually learns to reconcile the conflicting signals it receives from your inner ear (which feels the motion) and your eyes (which may see a stable horizon or cabin). This adjustment typically takes between 24 and 48 hours of continuous exposure. Many professional sailors and cruise passengers find that they feel quite ill on the first day but are perfectly fine for the remainder of the journey. However, this tolerance is often specific to a particular type of motion; you might habituate to a large cruise ship but still feel sick on a small sailboat. Interestingly, the brain can also develop "mal de debarquement"—where you feel as if you are still rocking after you return to dry land. To build tolerance effectively, it is recommended to spend time on deck looking at the horizon, as this helps your visual and vestibular systems synchronize more quickly than if you were to stay in a windowless cabin.