“Yo no tomo” or “no tomo gracias” (with tomo pronounced toe-moe”). I don’t speak more than casual tourist Spanish, but it means “I don’t drink”. Staff should get it and be polite about it.
Resort staff probably speak English too, but I like the Spanish, because it doesn’t clue every other English speaker in that I don’t drink.
I like saying this instead: “una Jamaica in vasa con hielo e lima”. Jamaica (ha-mike-a) is a non alcoholic hibiscus extract, I like it in a glass with ice (hey-lo) and lime. It’s delicous and looks like a cocktail. Truth be told, I feel like more a part of the party that way, and makes it easier to be social.
The bottom line is I love going to Mexico, I made a decision not to drink, and I’m not going to let sobriety keep me from fun in the sun.
Feel free to correct my Spanish tho.