Drive north from Townsville through Belgian Gardens and Rowes Bay towards Pallarenda. The road ends at a Quarantine Station. Follow the walking track up the hill, past some old World War 2 gun placements, and over the headland. You will get some great views of Magnetic Island. The track ends at a small beach which is fairly popular. At low tide you can skirt around the rocks at the far end to get to Shelley Beach, which is more secluded, and dispense with your costume. When the tide is in the only way to get there is climb over the rocks.