You can use either one you prefer or have on hand. Just make sure to thaw it first if using frozen mango chunks. If using fresh mango, it is really important to make sure the fruit is ripe. You absolutely do not want to use fruit that is not ripe enough. Ripe mangos are a must. The popsicles will not taste the same. Also, sometimes frozen fruit isn't as ripe as fresh and can be less sweet. You might find you need more sweetener if using frozen. This is based on preference so feel free to adjust the honey as needed.