Commercial whaling is a divisive issue in Iceland, and often considered to be irreconcilable with whale watching. The coexistence of both activities in Faxaflói Bay, adjacent to the capital city of Reykjavík, has led to the designation of part of the bay as a whale sanctuary, where whaling is banned. The study utilises the contingent valuation method to elicit the preferences of Icelanders and estimate their willingness to pay (WTP) to expand the sanctuary to the full extent of Faxaflói Bay, with an aim to inform marine spatial planning in Iceland. Using the double-bounded dichotomous approach, the mean WTP for expansion of the Faxaflói Bay Whale Sanctuary was estimated to be 5082 ISK/42 USD per person (1.32 billion ISK/10.9 million USD when multiplied by the number of taxpayers), and 29.7% of the respondents with clearly defined preferences expressed positive WTP. According to the logit regression model, statistically significant socioeconomic and attitudinal variables included age, gender, level of education, number of persons in a household, and attitudes towards environmental conservation and whaling. Policy implications of non-market valuation of marine ES are discussed, pointing to a need to further assess the multiple marine ES values applying a transdisciplinary approach to inform decision-making.