  We consider the well-known Boltzmann brains problem in frames of simple
phantom energy models with little rip and big rip singularity. It is showed
that these models (i) satisfy to observational data and (ii) may be free from
Boltzmann brains problem. The human observers in phantom models can exist only
in during for a certain period $t<t_{f}$ ($t_{f}$ is lifetime of universe) via
Bekenstein bound. If fraction of unordered observers in this part of universe
history is negligible in comparison with ordered observers than Boltzmann
brains problem doesn't appear. The bounds on model parameters derived from such
requirement don't contradict to allowable range from observational data.
