"Police have reviewed the information and confirmed the activity, and the number of people in the group, complied with the PHOs in force at that time.
"There will be no further police action taken."
Monday was a bright and sunny day, perfect for a boat trip in ordinary circumstances β but pictures of the celebrity outing raised eyebrows in Sydney due to the strict lockdown rules.
Sydney is in the grip of a worsening surge of the delta strain of the virus and has been under strict lockdown orders since June 26.
The rules tightened further on Friday after the state recorded 44 local daily cases, the worst result so far this year.
The new rules mean each Sydneysider can exercise outdoors with only one other person, unless they live together, and people must remain within 10km of their home for exercise or outdoor recreation.
The police spokeswoman's use of the phrase "at the time" was crucial β it's understood the trip counted as outdoor recreation, which was permissible for groups up to 10 people until Friday at 5pm.
Had the celebrities embarked on the same trip after the new rules came into place, it's possible police may have made a different determination.
Under the present stay-at-home rules, people are not allowed to leave their homes unless it's for essential activities such as exercise, grocery shopping, medical appointments or work that can't be done from home.
Earlier on Friday, NSW police said it had been made aware of "community concerns" about the boat trip and were investigating.
Baron Cohen, known for portraying the characters Borat and Ali G, is married to Aussie actor Isla Fisher and the pair moved to Australia last year.
Fisher last month told Marie Claire magazine that the move was temporary.
Black Swan star Portman came to Australia to shoot the Marvel blockbuster Thor: Love and Thunder, a mega-production that drew other stars Down Under as well, including Chris Hemsworth and Christian Bale.
