I can't remember where I read it, or if it's even "official" but I read that the Narrow Sea is akin to the English Channel.
Braavos is across the Narrow Sea. Meereen is leagues farther.
Arya's trip back is considerably shorter than that of Dany's fleet:
Meanwhie Sam and Gilly take four episodes to get from Horn Hill to Oldtown, two towns which are on the same side of the continent:
The most obvious answer is not always the first one considered.
And in your case, it's not the correct one.
The most obvious answer is that the showrunners are cheating with time & space to collapse plotlines and speed up the final confrontations in Westeros.
If the show moved at Martin's pace, the finale would occur in 2035!
And of course some amount of cheating must take place in a story of this scope.
The way the show has been edited together is what makes these spatial and temporal leaps questionable and hard to believe.
At the end of season five, the four ladies of Dorne watch from the shore of Sunspear as the doomed Myrcella sails away with Jamie and Trystane.
But Obara and Nymeria somehow catch up with that boat as soon as it gets to King’s Landing.
This is so that we could hear the Sand Snakes make jokes about killing their cousin, but it makes no sense within the realm of medieval travel times.
You guys are killing me with the time stuff. Do you really wants weeks of filler shows just so Vary's can travel from one place to another?
Hyperbole much? No one has said anything about filler shows full of travel except you.
Attentive viewers notice these things and may <gasp> dare to comment on them from time to time.
The show can still be enjoyed even if its plotting isn't airtight.
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