Interesting one. Not many people transit through Ashgabat.
From what I’ve seen, you’ll likely go through transit security again, even if you’re not entering Turkmenistan. If that’s the case, any large bottles of water from Istanbul probably won’t make it through. Standard liquid rules usually apply in transit screening.
Food is usually less of an issue as long as it’s solid and not something messy or liquid based.
With 11 hours, I’d plan on buying water after security in Istanbul for the first leg, but assume you may have to ditch it during transit. Worst case, bring an empty bottle and refill it if there’s a fountain in the transit area.
Ashgabat airport isn’t exactly known for tons of options, so packing snacks is smart. I just wouldn’t count on keeping large liquids the whole way.
0