Year 388 (CCCLXXXVIII) was a leap year starting on Saturday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Augustus without colleague (or, less frequently, year 1141 Ab urbe condita). The denomination 388 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

With the intent of forming a trans-Europe numbering plan as an option (or then future movement) for anyone needing multi-national European telephone presence, the ITU allocated country calling code +388 as a subdivided, catch-all container for such services. This was designated the European Telephony Numbering Space or ETNS.