EL Yunque is full of vibrant colors, plant life, and beautiful birds. It is located in the northeast part of island off of route 3 on the way to Fajardo. It makes for a great day trip, but make sure to plan at least a day if you wish to walk some trails, visit waterfalls, and really enjoy the nature.
The main drive through the rainforest takes you past a visitors center, a beautifully designed outdoor center with information about the rainforest. It is also a great place to ask for advice on which trail may be best for you.
The drive continues up, winding up towards the top of the small mountain. There are various places to stop along the way with trails and waterfalls. The park gates close at 6, so make sure to plan your trip accordingly.
Downside: You pretty much need a rental car to visit the rainforest. Public transportation on the island is challenging – the buses are unreliable and taxis are extremely expensive.