Preheat oven to 350°F (175C/150C Fan) and prepare two standard sized loaf pans. These can be greased and floured or lined with parchment paper.
In a medium bowl, stir together flour, cinnamon, baking soda, salt and baking powder.
In a large bowl, whisk together sugar, eggs, oil, pineapple, vanilla and zucchini.
Add the flour mixture to the wet ingredients until just combined (avoid over-beating).
Pour the batter into your prepared loaf tins, filling about ½ to ¾ full.
Bake until a skewer inserted in the middle comes out clean - checking regularly after 40 minutes.
Remove from the oven and allow to cool in the tin for a few minutes before turning out onto a baking rack to cool completely.