Originally, I had planned to go diving, but it seems that the wind is still strong this time of year, and no diving boats are operating on the west coast. So, I ended up taking a nap at the hotel, and also went on a boat tour to a nearby river.
I didn't have high expectations, but it was surprisingly comfortable, so I might come back to rest here a few more times in the future.
There seems to be a safari in the southeastern area with a variety of animals, so I'm thinking it might be a good idea to explore the surrounding jungle and mountains next.