Grease and line 2 loaf pans with parchment paper and preheat the oven to 350°F.
Combine flour, baking soda, cinnamon, and salt in a bowl; set aside.
Whisk together sugar and oil in a large bowl. Whisk in eggs, one at a time. Whisk in buttermilk and vanilla until blended. Stir in carrots and pineapple.
Add wet ingredients to dry ingredients just until blended. Fold in coconut and walnuts.
Pour batter evenly into two greased 9 x 4-inch loaf pans.
Bake until a cake tester inserted in centre comes out clean, about 65 - 70 minutes. Cool in pans on racks for 10 minutes. Place loaves onto racks and cool completely.
