Any water vessels that sail are considered “cruise ships” regardless of ship size. You can deduct these expenses only if all of the following requirements are met: The convention, seminar or meeting is directly related to your trade or business. The cruise ship is a vessel registered in the United States.

In 2026, the IRS maintains very strict and specific "luxury water travel" rules for deducting cruise expenses. You can generally only deduct a cruise if it is directly related to your business, such as attending a convention or seminar held on the ship. Even then, the deduction is capped at twice the highest federal per diem rate for travel in the United States, and the ship must be a U.S.-registered vessel with all ports of call in the U.S. or its possessions. Furthermore, you must provide a written statement from the convention sponsor detailing the daily schedule of business activities and your actual hours of attendance. If the cruise is primarily for a "working vacation" without a formal convention, you can typically only deduct the specific business-related costs, such as the cost of a meeting room or specific business meals, rather than the entire fare. Personal "lavish or extravagant" expenses remain strictly non-deductible, making a full "vacation cruise" deduction nearly impossible without a legitimate, documented business necessity that meets these rigorous federal criteria.