You can potentially write off a cruise as a business expense in 2026, but the IRS rules are extremely restrictive. To qualify, the cruise must be directly related to your trade or business. There are two main paths: Luxury Water Travel and Conventions. For general business travel by ship, the deduction is limited to twice the highest federal per diem rate. If attending a convention or seminar, the deduction is capped at $2,000 per year, and the ship must be a U.S.-registered vessel with all ports of call in the U.S. or its possessions (which is rare for major cruise lines). You must also provide a written statement signed by a convention officer detailing the total days spent on business activities. Because of the "recreational" nature of cruises, these write-offs are high-risk targets for audits.