Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Singapore to San Juan as you normally would.
Japan Airlines, United Airlines, and British Airways are some of the carriers that may have flexible cancellation policies. You can use our site to filter for other airlines that may also have this kind of flexibility.
Consider British Airways, Japan Airlines or United Airlines when booking your flight. These represent the most popular airlines when flying from Singapore to San Juan.