New Zealand-based Pacific Blue and long-haul offshoot V Australia are now operating under the Virgin Australia banner.
The rebranding, which was flagged earlier this year, went live yesterday.
It features new airport signs and travel documents, as well as a revamped Virgin Australia website that covers all of the airline group's domestic and international services.
The 17 Pacific Blue Boeing 737 aircraft, primarily based in New Zealand, will have their interiors refurbished in the first half of next year.
There are plans also for an update of the cabin interiors on the five V Australia Boeing 777-300ERs that fly to Los Angeles and Abu Dhabi.
"Now that our international airlines are all operating under the Virgin brand, our focus is on redesigning the product in the air to ensure a first-rate travel experience across all of our airlines," Virgin chief executive John Borghetti said in a statement.
Painting of the aircraft into the new livery was expected to occur when they went into service, to minimise disruption to schedules.
The one part of the airline group that does not fall under the Virgin Australia umbrella has also received a revamp, with Polynesian Blue renamed Virgin Samoa.
Virgin Samoa, which operates one Boeing 737 and flies from Apia to Sydney, Brisbane and Auckland, is a joint venture between Virgin Australia and Samoan government, which both own 49 per cent of the airline. Aggie Grey's Resort and Hotel holds the remaining shareholding.
Virgin closed steady at 35.5 cents.