The maximum length of stay allowed on a round-trip ticket is primarily determined by the "Maximum Stay" rule associated with your specific fare class, which can range from as little as 30 days to exactly one year. For most standard international commercial airline tickets, the absolute limit is 12 months because the global distribution systems used by airlines generally do not allow for bookings more than 330 to 365 days in advance. If you are traveling on a discount or promotional economy fare, the airline may restrict your stay to a much shorter window, such as 90 days. Beyond the airline's rules, your legal length of stay is governed by the visa and immigration laws of the destination country. For instance, many tourist visas or visa-waiver programs (like the Schengen Area or the U.S. ESTA) limit visitors to 90 days. Even if your airline ticket allows for a return in six months, you could face deportation or fines if you exceed your legal visa duration. For long-term travelers, it is often necessary to book "open" tickets or simply buy two one-way tickets to bypass the standard one-year technical limitation of the round-trip booking system.