Visiting Transnistria should not be a problem, both with entering it and leaving it from Ukraine and Moldova.
Transnistria controls the territory, and Moldova considers the territory its own part. This effectively means that Transnistria-Ukraine border is not controlled by Moldova even though Moldova treats tourists as visiting their territory. On the Transnistria-Moldova border they don’t have the border officials because it’s “internal” border, however they do have customs there so that one could do customs formalities because it’s the last point on the route through Transnistria where it is at all possible.
I visited Transnistria twice with entry/leave from Moldovan side in 2015 on a Ukrainian passport. Things to be aware of:
To my best knowledge Transnistria officials do not stamp passports. Instead you fill a form when you enter, then are supposed to pass its stamped part back when you leave Transnistria. There is no really a problem that getting stamped one might get problems elsewhere in future.
A few years ago, I visited both (on a Dutch passport). I traveled from the Ukraine, through Transnistria, to Moldova, by train. I got off the train in Moldova, then traveled to Transnistria, went through some formalities at the ‘border’ and returned to Moldova before traveling onwards.
If I remember correctly, getting off the train in Transnistria, from the Ukraine, was not advised, as that would have required me to travel back to the Ukraine before traveling onwards (if getting off the train was allowed in the first place).
Credit:stackoverflow.com‘