Do I need friends to play the game?

No, you don't need in-game friends to play the game, you can play on your own if you like. However, if you have Facebook or Game Center friends who are playing the game you can visit their resorts, look for treasure chests and send and receive gifts. You can also see in the leaderboards where your resort stands compared to your friends. You can also visit Naomi the resort guide's resort to look for treasure chests and treasure chests also appear in your own resort.