This paper finds that policy mixes for mobile broadband diffusion need to be differentiated depending on where a country is situated in three stages of mobile broadband diffusion because as a mobile broadband market grows, demand constraints hindering subscription of mobile broadband will also change. A total of 115 countries are clustered into three groups (Take-off, Fast-Diffusion, and Saturated), categorized by their diffusion rates and diffusion speeds over four years from 2013 to 2016. With pooled and fixed effect panel data models, this paper examines which variables out of 23 explanatory variables were effective in promoting mobile broadband adoption globally. Further, by interacting explanatory variables with two group dummies, this paper identifies differential slope (policy) effects of each explanatory variable on mobile broadband adoption. The paper concludes that, among the three groups, considerable gaps exist in the size of effective policy choice sets: six for Take-off, ten for Fast-diffusion, and thirteen for Saturated, suggesting that the countries in the Take-off stage have a very narrow degree of latitude for developing mobile broadband promotion strategies.