You will be able to buy food, nappies and wipes for your child in Cancun however, you may not be able to find the brand you are used to so consider bringing your essentials with you.
If you are breastfeeding, you will not encounter difficulties with breastfeeding publicly in Mexico. It is advisable to bring your child’s powdered formula to Mexico as you may not be able to get the brand your child is used to there. If you decide not to bring formula or if you run out then you can purchase local brands at Walmart and Oxxos.
When preparing bottles remember to use only bottled water and to sterilize the bottles after use. When bathing and swimming, ensure that your child does not ingest any water. Baby food is widely available and you will be able to find a good selection at Walmart. Nappies are widely available and can be purchased at Oxxos (a local convenience store chain) or in Walmart or at any number of local stores.
Baby carriers and slings are useful for visiting ruins but it is advisable to have a good stroller with you also for exploring towns and for just walking around as baby carriers can lead to overheating in hot climates if overused.