If there was such a place, then there are two possibilities: water level rose a lot, or ground level fell a lot. A combination of the two is also possible. The tale of rapid drowning of the metropolis suggests either a very large earthquake with major vertical land motion, or the breaching of a barrier to the open ocean when the metropolis was already located below sea level. This second idea is not consistent with the description of the ring island and surrounding harbor (hard to have open ocean and be isolated from open ocean at the same time).
It is remotely possible that sea level rose significantly and effectively instantaneously, causing the inundation of the coastal city. However, sea level rises of several meters is not really possible "instantaneously". There have been documented cases of glacial lake releases that could cause sea level rises of up toward one meter in depth over periods of a few months, so this is one possible way that a coastal city could be flooded rapidly, even if not completely. Having this occur during the major glacial melting periods of 10,000 years ago or so (and there were such events in that time frame) could, along with the significant overall rise of sea level through centuries, be an explanation for the loss of some ancient city.
It is far more likely that the Atlantis tale refers to an ancient city that was in an area, like perhaps the modern Persian Gulf, that was occupied land some 10,000 years or so ago, and that the flooding was not actually an instantaneous event, but instead an inexorable flooding over centuries.