No, a TWIC card cannot substitute a passport for international travel. A TWIC card is a Transportation Worker Identification Credential, a tamper-resistant card issued by the Transportation Security Administration (TSA) to maritime workers. It is not a valid travel document for international travel. To travel internationally, you need a valid passport from your country of citizenship. A key is a travel document that proves your identity and nationality. It is required for entry into most countries. There are a few exceptions to the passport requirement for international travel. For example, US citizens can travel to Canada and Mexico by land or sea without a passport. Still, they must have other proof of identity and citizenship, such as a driver’s license and birth certificate. However, there are no exceptions to the passport requirement for international travel by air. All passengers must have a valid passport to board an airplane, regardless of nationality. If you plan to travel internationally, check the passport requirements of the country you visit. You can find this information on the website of the country’s embassy or consulate.