Combine the frozen pineapple chunks, coconut milk, and ice in the blender.
Secure the lid and blend on high speed until the mixture is smooth and frosty, about 30-40 seconds. You should see a thick, icy consistency with no large chunks remaining.
Stop the blender and check the texture. If it’s too thick, add a splash more coconut milk; if too thin, add a few more ice cubes and blend briefly again.
Once the slushie is velvety and well-blended, pour it into glasses or cups.
Garnish with small pineapple pieces or a sprinkle of shredded coconut if desired for a festive presentation.
Serve immediately with a straw or spoon and enjoy the cool, tropical flavors.