"We went to Piha and it was frickin' fantastic. We had such a nice weekend there. We spent the entire time in the water. The kids spent six years in Hawaii when I was working on Lost so for them to get back in the surf was awesome, we had such a blast."
The family have gone home to Oregon and Fox says he is desperate to join them when filming ends next week.
"I'm really excited to go home. It's so hard for me being away from the three most important people in the world to me."
In the meantime, he has been indulging his love of wine - and has taken a particular liking to Waiheke Island's Destiny Bay vineyard. He visited the winery last weekend and met owners the Spratt family.
Fox says most fans recognise him as Jack out of epic TV fantasy Lost. "But honestly, I don't get recognised most of the time. I try to keep a low profile."
Today, the famously gruff Jones is off-limits for interviews. But he mingles freely with the crew, standing in line for lunch and sitting down to eat with co-workers.
Jones came to New Zealand with wife Dawn Laurel, and the couple flew to Queenstown for a sightseeing trip last weekend.
Jones has a special connection with the country: his eldest son Austin was born here in 1982 while he was filming pirate film Nate and Hayes.
Kiwi producer Tim Coddington worked on that film with Jones.
"I remember feeling sorry for Tommy at the time, having his first-born son while he was filming," Coddington says.
The cast and extras spent up to 18 hours on set yesterday as Whenuapai was turned into Atsugi Airfield in Japan, where MacArthur arrived in August, 1945, to accept the Japanese surrender.
The production team had earlier turned Southdown Freezing Works into war-ravaged Tokyo.
Director Peter Webber, whose credits include The Girl With the Pearl Earring, says it is a great showcase for New Zealand filmmaking. The Kiwi-dominated crew has brought a refreshing "can-do" attitude.
"In some countries you get this thing where people are a bit like 'oh that's not my department' but here everyone mucks in."
The film deals with whether Japan's wartime ruler, Emperor Hirohito, should be tried and hanged as a war criminal - a subject that Webber says still resonates today.
"The Americans dealt with this in 1945 - I would argue with more intelligence than the situation was handled in Iraq. Japan rose from the ashes and the rubble and became a world power."