This paper is motivated by recent debates about marine spatial planning (MSP) and a blue economy, pushed worldwide for marine and coastal transitions but discussed by critical scholars as potentially facilitating a neoliberalization of the seas. It engages with an MSP project initiated in Auckland, Aotearoa New Zealand, to formally bargain for a better socionatural state of the Hauraki Gulf Tīkapa Moana (Sea Change Tai Timu Tai Pari, 2013–2016). The paper is interested in the way ethics—proper ways of living—are being problematized and (re)claimed in MSP, and their role in remapping the land/seascape, its socionature and power relations. I employ and develop urban ethics as a research agenda, which draws together a diverse scope of work, in particular post-political theory, neoliberal forms of governing and ethicization, ontological pluralism and (re)centering alternative/non-hegemonic ethicalities. By disentangling the problematizations, naturalcultural imaginaries and governmentalities in 21 in-depth interviews, I identify four distinct but interwoven discursive strands in regard to the MSP. Two strands stand out as they problematize ethics as a means of change. The paper finds transformative potential in a mode of disruption and progressive alternatives to neoliberal beliefs and governmentality, primarily in the (re)centering of non-normative Māori ethicality and knowledge. The paper reveals ethics as a major dimension in environmental bargaining within a neoliberal urban context. Its nuanced understanding of ethics shows ethics’ destabilizing role in environmental bargaining, its role in disrupting power structures and colonizing framings, and in supporting alternative imaginations of socionatural land/sea relations.