I just came off Symphony. A few patches of higher seas here and there in the wind near Aruba- we did Southern Caribbean. Honestly it was nearly impossible most of the time to feel ANY motion on the ship at all. Rock stable. I was impressed with how smooth it was. We were in the center on the highest deck (17). But all over the ship it was unusual to feel any motion. I know anything can happen at sea, but this ship is a very good choice to avoid motion. We brought some ginger chews just in case, but never had a need to use them. Several of the shops on board carried motion sickness medications up near the checkouts.