There is no given date in the actual play that implies when All's Well that Ends Well is set. We do know a few bits of information that might be helpful, though. For example, we know the play was probably written around 1603. One could potentially look to the "Tuscan wars" for evidence of the time period, but we know that these were invented by Shakespeare as a plot device. In many ways All's Well that Ends Well is very akin to Shakespeare's romances -- The Winter's Tale, The Tempest, Pericles and Cymbeline -- and despite being mostly a comedy, there are magical/fairy tale elements to All's Well that Ends Well that evoke a sense of timelessness. If we see it as a fantasy, it isn't of much importance when the play is set. It's likely that it could have been set in Elizabethan times, since we know the play isn't set in an ancient time as Julius Caesar, for example, is.