The emirates of Abu Dhabi and Ras Al Khaimah have emerged as frontrunners to introduce casinos before their neighbor Dubai, after the glitzier city-state put any immediate plans to allow gambling on the backburner, according to people familiar with the matter.

After the United Arab Emirates set up a framework for legalized gaming in September, Abu Dhabi is mapping out what it would look like to open a casino, with Yas Island — home to the Ferrari World and Warner Bros. theme parks, as well as the Yas Marina Formula One Circuit — and a plot near the city’s port among the sites being considered, some of the people said, asking not to be identified because the discussions are private.