Yes, and this is the item to get right. Waterproof pants may be required for every Zodiac operation and landing, and they handle sea spray, rain, wet snow, damp Zodiac tubes and wet landings. Water-resistant hiking pants and most softshells are not a substitute. Look for the word waterproof rather than water repellent or water resistant, with sealed or taped seams.
Fit matters as much as the fabric. The pants need enough room to go over your insulating layers and over the outside of the expedition boots, with a hem that isn't tight at the calf or ankle. Full-length side zips or generous ankle zips make dressing in a crowded mudroom much easier.
Wear them when the expedition team asks, even on a dry-looking morning. Conditions change after the Zodiac leaves the ship and the return ride is often wetter than the outbound one. Operator safety rules take priority over personal preference here.