Pulsation-assisted fluidization was employed in a square fluidized bed to enhance mixing properties. The gas-phase pulsation frequency was varied between 0.5 and 5.0 Hz. The fluidized bed hydrodynamics were studied with and without internals, in beds of different heights. From the measurement of pressure fluctuations, average cycle frequencies (ACF) and incoherent standard deviations (lop) were calculated to quantify bubble characteristics, such as the bubble size. In addition, optical probe measurements were used to determine the local bubble fraction. When a fraction of the total flow is oscillated with an appropriate frequency, possible defluidization problems are prevented. A clear change in the bubble characteristics was observed when increasing the pulsation frequency up to 3.0 Hz. Higher pulsation frequencies, especially beyond 5.0 Hz, have no significant effect when compared to a steady, constant flow. Pulsation-assisted flow significantly increases bubble size, increases the ACF, and decreases bubble fraction. Moreover, the presence of internals slightly decreases the bubble size, slightly decreases the ACF, significantly decreases the bubble fraction, and influences the bubble pathway, especially at low superficial gas velocity. Finally, increasing the bed height has a less clear trend on the ACF, but it increases the bubble size using either steady or pulsed flow, with more significant increases in the latter case.