From a CDFG Press Release: California Outdoors Q&A

Question: I am not completely clear on the amount of abalone we are allowed to give to a family member in a day. I understand the limit is three abalone per day and three in possession. I plan to take my 10-year-old son and my 7-year-old daughter with me. If we can bring back nine abalone over a three-day period, and all of us are in the truck at the same time with our abalone, would we be considered legal? It is important that the answer you give me be consistent with the wardens on the North Coast as they are the ones who will be issuing the ticket, which I choose to avoid. Not only that, my kids will be with me so I don’t want to be arrested. (Richard M., Sacramento)

Answer: Rest assured, Richard, the laws on abalone are pretty clear. Each person with a valid fishing license and a valid abalone report card is allowed to personally take three abalone per day, have no more than three abalone in possession, and to take no more than 24 per year. You are authorized to gift your abalone to another person, but you may never take more than three abalone in one day. This means that over a three-day period, you may take three abalone per day each day as long as you gift your abalone to another person before going back in the water for more the next day. You must tag and record all of your abalone you take each day on your abalone report card. The abalone must then remain in their shells with the tags still attached until they are ready for immediate consumption.

By abiding by these regulations, you will be legal. If you're stopped along the way, the game warden will see from your report card that you have taken three abalone per day over a three-day period (for a total of nine). And each of your children's abalone that you have gifted them will have your tags attached to the shells that will then correspond back to your abalone card.