**The Ongo Niua 17 by-election, set for 8 October 2026, fills the Tongan Legislative Assembly seat vacated after Lataifaingataʻa Tangimana resigned following his conviction for election bribery in the 2025 general election, which also imposed a five-year disqualification.** Five independent candidates registered in early September, each drawing support primarily from their home villages in the small Niuas constituency: ʻAminiasi Tonga Pauʻu Tangimana and Sione Tuifio Hui from Falehau, Sitiveni Selui and ʻAisake Hoatatau Finau from Vaipoa, and Paea ʻi Vaha Filimoehala from ʻEsia. With no national parties involved and limited voter rolls, trader pricing on Polymarket remains tightly clustered around the top names because outcomes hinge on localized turnout, personal networks, and village-level mobilization rather than broad polling trends or incumbency. The fragmented field and modest electorate size mean minor shifts in participation or informal endorsements could quickly widen gaps before polls close. No major late developments have altered the balance in recent weeks.