Starboard side by the pool (deck 12). The whole starboard side on deck 7. The casino and the cigar lounge (deck 6). The Dawn is one of the most smoker considerate ships.
I'm a former smoker (almost 6 months) after the worse ship for smokers I've ever been on, Carnival Paradise. I was given a JUUL for Christmas from my husband. I was only intending to use it during airport confinements. I was so fed up after the 1st day on the Paradise that I started ducking into the nearest convenient bathroom to use the JUUL. Also in the stateroom. There is no odor. Although I was pretty ticked off at the time, this is the best thing that's ever happened! It's total freedom! No more panic on "where can I smoke". You'd be surprised how easy it is to get away with using it discretely. I've even done it on airplanes.
Oh, and I will NEVER be one of those "former smokers" who looks down their noses at current smokers. After smoking for 40 plus years, my heart is still with you all!