The single supplement is a premium surcharge applied to a traveler who travels alone but will use a room that could fit two or more passengers. Accommodation vendors argue that solo travelers should expect to pay for the luxury and convenience of having a room to themselves.

A single supplement is a surcharge added to the price of a travel booking, such as a cruise or a guided tour, when a solo traveler occupies a room designed for two people. In 2026, most travel pricing models are based on "double occupancy," meaning the advertised per-person rate assumes the cost of the cabin or hotel room is split between two guests. Because the travel provider (like a cruise line) loses the potential revenue from a second guest—who would typically spend money on drinks, excursions, and specialty dining—they charge the solo traveler a supplement to make up the difference. This fee can range from 25% to 100% of the standard per-person rate. However, a growing trend in 2026 is the introduction of "Studio" or "Solo" cabins on newer ships, which are specifically designed for one person and often waive the supplement entirely, making solo travel more accessible and affordable than in previous decades.