In English, if someone has been gone for a while and has recently returned, it's common to greet them by saying, "Welcome back!" (or "Welcome back from your trip!", etc). What is the most natural way to say this in Spanish? Bienvenido de regreso sounds a little awkward to my (non-native) ears. Is that the only option, or is there something more common people would say in these situations?
In Spain is not usual to use "Welcome back!", at least I do not use it.
In my experience, I have a friend who had gone to Scotland to live four months ago, last week he arrived to Spain and all of us said "¡Bienvenido!".
If I translate "Welcome back!" I would say "¡Bienvenido de nuevo!" interpreting more than translating it, or "¡Bienvenido otra vez!".
I think that expression, at least in Spain, has no translation from English.
No, "¡Bienvenido de regreso!" is definitely not correct, as Zhen points out it is a cacophony. In all cases of translation, if you are not trying to convey spoken language (a truly hard task, as you need to know both the source and target dialect pretty well), then you should guide yourself by the use in the written language. In that same venue, "¡Bienvenido de vuelta!" isn't correct either. But, the use of the imperative verb conjugation (one of the subtle uses of the accusative case in the Spanish language), is perfectly legal and will make you sound both warm and educated: "¡Se bienvenido!", "¡Seas bienvenido!"
Usually, in a return, we would use "Que alegria que regresaras!" (It's a pleasure to have you back) or "Gracias por regresar!" (Thanks for comming back) but there's no language translation exact to Welcome Back! The exclamation point and welcome do refer to happiness about the event being expressed and because of this, I offered happy sentences that could be used in such situations.
Generalmente en paises de habla hispana no se tendría en cuenta el hecho de que el individuo ha regresado "de nuevo". Si quien pregunta sigue insistiendo en la necesidad de traducir "Welcome back" literalmente, los comentarios anteriores son algunas buenas sugerencias. Sin embargo, este tipo de discrepancias son las que hacen especiales a los idiomas, pues cada uno de ellos percibe la realidad de maneras ligeramente diferentes.
In general, people in Spanish-speaking countries wouldn't take into account the fact that the individual has "come back again." If this thread's poster still wants to translate "welcome back" literary, the above comments are some possible suggestions. However, this kind of discrepancies make languages special, for every language perceives reality in slightly different ways.