We did the El Yunque/Bio Bay excursion. The tour guide, Debbie, was very nice and did a great job. Since this excursion combines two tours into one, it's a long day (12 hours total) but we preferred to do it that way.
El Yunque- the bus drives up to the tower that overlooks the rain forest and has beautiful views of the island. Then we went to the waterfall for photos and then a brief hike (15 mins each way) to a beautiful river where you can either swim or relax by the rocks. There is not very much "hiking" except to the river, so you basically get the benefits of the view without all of the hard work!
There's a pit stop before the Bio Bay excursion where you have about 1.5 hours to grab dinner or relax on the beach.
Bio Bay- this tour is led by a separate company, but Fine Line still covers transportation to and from the excursion. One piece of advice would be to bring some dry clothes to quickly change into after the tour. While we all had swimsuits on and towels to wrap up in, it was a cold/wet hour-long ride back to the hotels. read more