Drawing on primary research on trade unions that mobilise women workers in the informal sector in Tamil Nadu, the possibilities for diverse union strategies to emerge, sustain themselves over time, and even win contingent victories in particular contexts are enquired into. Ethnographic accounts of union struggles highlight when trade unions resort to workplace-based activism for wages and when they prioritise agendas such as skill-enhancement, “development,” or workers’ welfare rights. What conjuncture of local contexts and circumstances enables one and which makes the other necessary? A discussion on three case studies shows how both “old” and “new” forms of collective organising co-constitute trade union activism involving women labouring in precarious livelihoods in the informal sector. © 2019 Economic and Political Weekly. All rights reserved.