During the wash cycle, when the heater comes on to heat the water, that is the point at which the dishwasher is drawing the most current. Is there anything else on the circuit that the dishwasher is connected to? If so, move that other electrical device to a different circuit. I have seen instances where the circuit is shared with a refrigerator, freezer or dehumidifier. If the dishwasher is in a wash/heat cycle and the refrigeration compressor on the same circuit as the dishwasher starts up, that will trip the breaker.
Nuisance tripping can occur if the breaker that the dishwasher is hooked to is a GFI breaker or if the breaker is weak. In this case, replace the breaker with a standard properly rated circuit breaker.