Nuku Alofa Tonga. Low-lying Tongatapu (Sacred South) is Tonga’s main island – and the landing and launching pad for most adventures in Tonga. Around two-thirds of Tonga’s 106,000 residents live here, most of them in the capital Nuku’alofa (Abode of Love – how romantic), also home to the royal family. Outside Nuku’alofa, the island is a patchwork of dark-brown agricultural plots, small villages, a few chilled-out resorts.