Validity refers to when the visa expires. For example, a three month visa means you have three months from the date the visa is issued to enter and depart São Tomé and Principe. The exact validity of your visa will be written on your actual visa. What is An “Entry” (Single / Double / Multiple)? Single entry visas allow you to enter São Tomé and Principe one time within the validity of the visa. Double entry visas allow you to enter São Tomé and Principe two times within the validity of the visa. Multiple entry visas allow you to enter São Tomé and Principe an unlimited amount of times within the validity of the visa.