Slice the ripe watermelon into manageable chunks using a sharp knife on the cutting board.
Assemble the hand-crank juicer and pour the watermelon chunks into the feeding chute.
Turn the handle steadily to press the watermelon, watching the vibrant red juice flow into a collection vessel below. Continue until all chunks are processed, noting the separation of juice from pulp and seeds.
Once juicing is complete, pour the freshly extracted juice through a fine sieve for optional seed removal and to achieve a smoother consistency.
Pour the juice into glasses, serve immediately, and enjoy the bright color and refreshing aroma.