In the diving world, when we talk about 'superficial dives' we mean dives that are not deep dives. That is to say, for example, according to PADI -as one reference source, a deep dive is any dive deeper than 18m. Though every different diving association worlwide show slight differences there. That, however, does not mean a superficial dive is any dive at 18m or less. It is a very vague conception there, but, divers we consider roughly that a superficial dive would be any dive at 10-12 m or less. I am a professional-level diver certified by PADI with over 700 dives, and this is lingo we use in English everywhere. Spanish speakers we use this expression normally as the direct translation of 'inmersiones superficiales' makes no sense. In any case, we would not be talking about "zambullida", that is just goins for a dip. And yes, this is scuba diving, not snorkelling. When you do snorkelling, you are not actually diving ;).

Hope that helps. :-)



--------------------------------------------------
Note added at 12 horas (2013-12-02 13:46:27 GMT)
--------------------------------------------------

It might be more appealling to maybe some general ears, and suitable if talking about snorkelling, but again this is not what it means, not if you go to specifics and I wouln not even use it in a more general contex. "Zambullida" is just ould not a correct translation, even if you want to transcreate, technically speaking is just not what it means. If this for a dive resort it would not give it a very reputable name to call "zambullidas" to superficial dives. I would not actually trust a dive shop using that terminology at all. Your decision but I would definitely suggest, if in doubt, to ask the client and the audience this is addressed to.

PS: Apnea diving or also called free diving (no use of scuba tank) can reach even 100m or deeper, which is not superficial at all, while recreational scuba diving depth limit is 40m. Beyong that depth we'd be talking about technical diving, a whole lot another story.