Matapa Chasm is a narrow sea inlet cut into the coral limestone cliffs on Niue's north coast, about 15 kilometres from Alofi. The water in the chasm is extraordinarily clear — you can see the bottom at 10 metres without difficulty — and the sheltered walls protect it from ocean swell, making it one of the calmest and most beautiful swimming places on the island.
The chasm is accessed via a short track from the road. Steps lead down to the water, which is deep enough to dive into at high tide. Snorkelling is excellent — the coral walls are alive with fish and the visibility rivals the island's best dive sites. Go at high tide for the safest and most enjoyable swim. The drive north from Alofi along the coastal road passes several other notable sites; combine Matapa with the Talava Arches or Limu Pools for a full day out.