The former Xena: Warrior Princess star said she volunteered for the action because it was "a fascinating personal experience. When am I ever going to go into Arctic water again in my life?
"And because it's being bodily part of something which sends what I believe to be the right message."
Lawless was not scared about going into the ocean. There were "incredible safety protocols", and she and the other protesters would stay outside the rig's 500-metre exclusion zone.
She expected the action to take around two hours from leaving the Arctic Sunrise to returning. But "everything depends on climactic events... things can change on a dime out on the ocean".
The action was part of the Greenpeace protest bringing about a global awareness. "We'll take photos, hang banners, put messaging out around the world. It's to impress upon the Norwegian government that many thousands of people are behind Greenpeace... to stop new Arctic drilling."
The Norwegian government has allowed Statoil to drill in the Barents Sea.
It was Lawless's fifth day as part of the protest, and she expected to be aboard Arctic Sunrise for two more. Weather today was "very good" but "the first day was pretty brutal on the water".
Lawless has said she is protesting climate change for the sake of her children and future generations.
"We know beyond a doubt that we can't burn a single barrel of oil from a new well if we are to avoid a climate catastrophe," she said.
"I don't ever want to look my kids in the eye and explain why I didn't do all I could to protect them from climate change."
