Upvote:-1
A "round trip" figures largely in
To customs enforcement, you enter their country and you leave it, and that's all. Whether you are going somewhere or coming back or just wandering is something they neither know nor care.
Upvote:2
Typically, a single transit visa is for a single journey whereby you enter the country you transit and leave it again, soon. If you want to transit again on your return trip, you will either need a second transit visa or a double-entry (or similar; names may vary) visa.
For example, last year when I took a train tour through Russia, we initially transited Belarus. The tour was destined to end in Moscow; some people decided to take a train back from Moscow via Belarus again; they were notified that they will need a double-entry Belarusian visa. Others flew home from Moscow so they only required single-entry Belarusian visa. The cost of a double-entry was higher than single entry, but less than two single entries iirc.
The exact conditions depend on the countries youβre transiting.