Say at a critical temperature $T_c$ there is a phase transition.
If we had water, $T_c$ for the liquid-solid transition is $0 ^\circ$C. If we left a block of ice at $1 ^\circ$C for a bit, it will melt completely so that the whole thing is in liquid form. The two states (solid and liquid) will coexist for some time, depending on how much heat is being pumped in I presume, but then only once of them will remain.
For a Bose-Einstein condensate (BEC), however, we find this kind of graph:
where $N$ is the total number of particles and $N_0$ is the number or particles that collapsed to a BEC. At any given temperature, their ratio is fixed and the two states therefore coexist.
A book that I was reading compared the BEC phase transition to the vapour-liquid one, where droplet of condensed fluid coexist with gas... really?