I just got back from a trip to Puerto Rico and I was able to take my 18 and 19 year old daughters on a zipline adventure with Rain Forest Zipline Corp. The resort we stayed at recommended this company so we felt like it was a safe choice. We had never ziplined before and were a little apprehensive but this course is perfect for beginners. There are 9 lines. Most were easy, however, one requires a 3 story climb and another allowes you to go around 55 mph. The staff was very friendly and made us feel safe. It was cool to zipline through the El Yunque rain forest and the total time for this excursion was around 2 hours.