The best time to go crabbing is when the water is moving, according to Crab Tips. This is dependent on the region of the world, but in general, the best time for crabbing is early morning and at high tide, especially when they occur at the same time.
It is important to check local tide charts, and begin crabbing approximately two hours before dawn, whenever the water is moving. From a period of two hours before high tide through to two hours after is when the most crabs will be caught. Crabs may also be caught at low tide, if the water is moving.
Local laws state the earliest time of day crab traps are allowed to be dropped.