Three small sandy coves just south of Cat Ba Town — Cat Co 1, 2, and 3 — provide the island's most accessible swimming. They are connected by a cliff path cut into the karst, which is itself worth walking for the views back across the bay. The water is reasonably clear in calm weather and the swimming is sheltered.
Cat Co 1 is the largest and most developed, with a hotel complex behind it and parasols for hire. Cat Co 2 is the prettiest and quietest, undeveloped and reached only on foot. Cat Co 3 is the closest to town and gets the busiest at weekends. All three are about 10 minutes by motorbike or 30 minutes on foot from the seafront. Lifeguards in season; avoid swimming in rough weather as the water gets churned up.