If you don’t already know you should. Puerto Rico is a US territory and the US dollar is the currency of the island. Additionally, no passport is required to enter or freely travel throughout the island. The people of Puerto Rico are warm, friendly, giving and helpful. While PR is a US territory Spanish is the native language and it would benefit all travelers to say Hola, or either gracias. If you know the language congratulations, if not try to learn just a little as the locals appreciate your efforts.
