I received these as a gift while I was pregnant and didn't use them until my daughter was just under 1 year old. They do leak. A lot. They also feel pretty flimsy and cheap. I now use them for smoothies sometimes and stick a straw in but I don't let my daughter walk around with these cups as water would be everywhere.

I hate to say this because I love Ziploc, but man, these are the worst toddler sippy cups I've ever had. When I purchased these I was thrilled because they are made by Ziploc and I had such high hopes for them because of that. Well, much to my disappointment, these cups leak, they are not sealed well at all so where the top screws on leaks, if they are dropped the top pops right off, if you lay them down, as most toddlers do, they leak. It is ridiculous. I feel horrible that I did it again. Saw a great deal at Walmart and fell for it yet again. I mean, I thought Ziploc, first years, great price, perfect!!! WELL I WAS WRONG! I would not recommend these to anyone. I bought two boxes and I am so disappointed.