In the first half of the final episode of Season 6 of Game of Thrones (Winds of Winter), we see Varys
in Dorne, speaking with the Queen of Thorns and the Sand Snakes
In the last scene, we see him
traveling with Daenerys on a ship across the Narrow Sea from Meereen to Westeros.
Does he have a special mode of travel, or is the storytelling non-linear enough that the timeline fits?
The answer to the same question I posted on Movies.SE
The creators of the show have already said that the timelines of different places is not in sync. Some places move forward in hours, some in days and some in months.
Writer Bryan Cogman, who wrote episodes 6 & 7 of season 6 had this to say
The timelines between the various storylines don’t necessarily line up within a given episode. For instance, the ‘Northern Tour’ Jon and Sansa embark on would probably take a couple weeks, but Arya’s storyline over the past few episodes only spans a few days. We realized a while ago that if we tied ourselves in knots trying to make all the ‘story days’ line up between all the characters the momentum would suffer.
Varys leaves Mereen in episode 8. He is seen in Dorne in episode 10. So, that's believable. He gathers the support of Dorne and Tyrell ships and goes back in the same episode to Mereen. Varys doesn't have teleportation power because you can see Tyrell and Dorne ships along with Greyjoy and Targaryian ships in the naval fleet of Dany. You can't teleport ships so it is to be assumed that Varys sent a word back to Tyrion telling him that Tyrell and Martels are behind Dany now, so wait up. Varys must have got back with a token ship of Tyrell and Martel each with some envoys to prove their support.
Screenshots of Martells & Tyrells ships with sunspear & rose as the banner:
House Tyrell ships - So Timewise we can assume Varys Travelled to Dorne and back with the Martell and Tyrell fleet.
Tyrell sails, Martell Sails, and Targayen Sails - How Varys Returned to Slavers/ Dragons Bay
The storyline is non linear enough. We don't know for sure how much time passed between the scene in Dorne and the scene in the Narrow Sea.
Something that might help make the timeline make more sense:
Observant fans noticed the presence of Dornish and Tyrell ships in Dany's fleet, so we can guess that the scene takes place some time later. At least long enough for the ships of Dorne and Highgarden to mobilize.
I found the "timeline explanation" to be a bit clumsy and thought it was a production mistake, so I dug a bit and found an interview* with Conleth Hill, the Varys actor, where he answered this very question!:
I still wanna know how he got from lady Olenna and all the people in Dorne to Daenerys on the boat so fast.
Conleth Hill answered:
I don't think he did, you just didn't see the intervening time, it was just a cut.
According to this map, Dorne which is Sunspear, is accessible via sea from Slaver's Bay thru Volantis, a much shorter way compare to going by King's Landing through the lands before Volantis.
Varys left a good many days before the war against Mereen started. So many things happened since he left and returned. And of course, each character's arc doesn't need to go in chronological order or linear timeline. Daenerys did say Mereen is finally at peace. This meant it likely took a significant amount of time before they finally set sail towards Westeros.
