Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 12 cup Bundt pan.
In a medium bowl, combine flour, baking soda, and salt. Set aside.
In a large bowl, cream together butter and sugar until light and fluffy. Beat in eggs one at a time, then stir in vanilla extract.
Stir in the pineapple, banana, coconut and buttermilk. Beat in the flour mixture until just blended.
Pour the batter into the prepared pan. Bake for 45 to 50 minutes in the preheated oven, or until a toothpick inserted into the center of the cake comes out clean.
Allow cake to cool in the pan for 10 minutes, then turn out onto a wire rack and cool completely.
Interesting Facts
Coconut was first introduced to the Caribbean Islands in the 16th century.
Bananas are native to Southeast Asia, but they are now grown in tropical and subtropical climates worldwide.