You know the tourism industry is booming when operators start investing in their capacity and growth.

And that's exactly what the region's biggest reef tour operator is doing.

Quicksilver is spending more than $2 million on a major refurb of its Agincourt 3 platform and its flagship vessel Quicksilver VIII.

It is a monumental undertaking. The Agincourt 3 platform is 50 metres long, weighs 120 tonnes and features two stories overlooking the reef and one below the water.

Just towing it back into the port of Cairns for the refurbishment work takes more than 30 hours.

Once in port it was "taken apart like Lego" and worked on for 10 weeks before being reassembled and returned to the Reef yesterday.

It's expected to be operational again by the end of the week. 

Quicksilver Group managing director Tony Baker said the investment in Agincourt 3 - the largest platform on the Great Barrier Reef - was its first complete refurb in over 20 years.

The flow-on effects of this investment for our local marine and shipyard sector is also noteworthy.

"The refurbishment was in excess of $1 million along with the $1 million refurbishment of the iconic Quicksilver VIII, and we will continue to invest in our products to enable our guests to enjoy a premium reef experience," he said.

"The Quicksilver Group is committed to providing a range of reef experiences for travellers that come each day to enjoy and explore the wonders of the Reef.

"I am sure when Agincourt 3 platform returns home she will once again see the silence of the seas, watch whales breach and see the coral spawn as the Great Barrier Reef lives and breathes around her."

The investment by Quicksilver comes on the back of multi-million dollar refurbs by the region's hotels, such as the Sheraton Mirage at Port Douglas, and continued strength in airport passenger numbers.

The most recent tourism visitation survey confirmed the good news for our local industry.

According to Herron Todd White's Rick Carr, international and domestic terminals at Cairns Airport continue to shine.

"Passenger number trends at Cairns Airport have come down a touch from the high levels experienced earlier this year, but are nevertheless maintaining strength at both the international and domestic terminals," he said.

"Airport passenger numbers for 2015-16 as a whole increased by 7 per cent on those recorded in 2014-15, fuelled by 5.2 per cent growth in the domestic terminal and 20.6 per cent growth in the international.

"Cairns Airport notes that its highlights in June included Jin Air announcing seasonal flights between Seoul and Cairns starting in December 2016 (subject to government approval), and the Cairns Airport Adventure Festival, which attracted record numbers of participants (and thousands of bicycles) through the airport."