Entering Guangzhou / Shenzhen from HongKong

Indeed, if you plan to take a route:

Hong Kong - Guangzhou - Hong Kong

You need a visa for such an itinerary because Guangzhou does not offer any VOA and you cannot use visa free transit option also because this is a return trip and not a transit.

I have a solution for you:

1. A flight from Hong Kong to Guangzhou because you become eligible for 144 hour visa free transit only if you fly into Guangdong province
2. Stay and travel within the entire Guangdong province, Shenzhen included, of course.
3. Take a ferry from Shekou port in Shenzhen to Macau by booking a ticket for this ferry in advance through TurboJet website. Also, you have to print out that ticket and have it with you as a proof that you are really in transit. You have to take exactly that ferry you have bought the ticket for.

Like this your itinerary is:

Hong Kong - Guangdong province (mainland China) - Macau

This itinerary is eligible for 144 hour visa free transit. Also, Macau and Hong Kong are so close to each other that you can return to Hong Kong as soon as you reach Macau.

Thank you for your reply Borut. Appreciate it! How about land transfer from Hong Kong to Shenzhen with the Macau ferry ticket as proof in this case instead of flying from Hongkong to Guangzhou?

Will we be eligible for the 144hrs visa free transit?

I'm afraid you cannot transfer on land, as this policy is only eligible for a flight entering Shenzhen.