Start by 12 months. Start offering small amounts of water and breast milk or formula in a cup between 9 and 12 months of age. Then start working on weaning from the bottle at 12 months. Toddlers should be off the bottle completely between 15-18 months of age. The older a child gets, the harder it is for them emotionally, so it's best to start early.
Begin at 1 year. The american academy of pediatrics recommends beginning the weaning process from bottle to cup at or before one year. Children should be off the bottle by between 15-18 months old. Weaning can sometimes be difficult; one method to try is to only offer milk from the sippy cup, not the bottle. Starting early helps the weaning process.
Bottle+ water at 1 . Some are easy to convert some not.If you put water in a kids bottle rather than what they expect, they must choose whether they like the bottle more than what they're drinking. Water is boring, they'll toss it aside unless attached to the bottle and the tears are not worth it. Put the good stuff in sippy cups and be firm, no milk in the bottle.They eventually choose the good stuff.
1 year old. Simple answer. Age 1, end of story...