Yes but I only do this if I'm planning to thaw and bake with them. In fact, I always have whole unpeeled bananas in my freezer. Once I want to bake something like banana bread, I take them out, place in a bowl and wait for them to thaw, which usually takes under an hour. Once you remove the peel you will notice that the banana almost turned to thick liquid. That's fine - it's perfect for baking!