If you come to Port Antonio you should not miss the "Reach Falls" either. These falls in the middle of the jungle are very popular among tourists since a memorable scene of "cocktail" was shot there.
If you like hiking, you should follow a narrow path that will take you to Mandigo Cave, with its whirlpool.
To get to Reach Falls you will have to hire a private taxi. It is not possible to get there on public transport. Ask the tourist office in downtown Port Antonio for more information on how to get there.