I will only be in the Willemstad port 6 hours. What are the best things to see or do?
The absolute best thing would be to rent a car and drive around the whole island, you can easily do this and be back in Willemstad in less than six hours. I would book car online before arrival, because you risk high prices or no availability. Make sure your pickup is Willemstad city center. You also could book a tour, if you don't feel like driving, there are half day tours leaving from most hotels. Tours fill up fast too, book in advance!
Depending on what you like to do, there are beautiful beaches, a lake with flamingos
Walking around Willemstad isn't bad, there are plenty of nooks and crannies, just be aware of your surroundings. There were fabulous vacant, decaying properties and plenty of bars just to hang out and drink if all else fails.
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