Virgin Australia has launched codeshare services with Virgin America in conjunction of this year's Fourth of July celebrations.

Starting 17 July 2012, Virgin Australia will codeshare on Virgin America services from Los Angeles to a total of 25 codeshare destinations and over 300 interline destinations across North America, including eight major cities such as Washington, Dallas, Chicago, Portland, Boston, Fort Lauderdale, Philadelphia and Seattle.

The new codeshare agreement effectively enables Virgin Australia to broaden its extensive network within the United States.

"The United States is a very important market for Australia; it is the third most popular international destination for Australian visitors and our fourth biggest source of overseas visitors to Australia," Merren McArthur, Virgin Australia group executive of alliances, network and yield, said in a statement. "We are delighted to offer Virgin Australia guests access to Virgin America services in the United States and to offer them frequent flyer recognition throughout the journey."

Meanwhile, travellers departing and returning to Australia can now travel around the world as Virgin Australia on Tuesday launched with alliance partner Singapore Airlines the new Round the World and Pacific circle fares.

The Round the World fares start from $2,264 to 85 destinations in 35 countries. A transatlantic crossing and a transpacific crossing is required to form part of a Round the World fare and can only occur once on the fare, with a side trip from Singapore to Asia permitted.

With 36 destinations in 13 countries, the Circle Pacific fares start from $1,969. A South Pacific crossing and a North / Central Pacific crossing must form part of a Circle Pacific fare and can only occur once on the fare, with a side trip from Singapore to South-East Asia also permitted.

There are no restrictions on eligibility or the total number of stops made or minimum stays.

"Customers now have the benefit of being able to travel from all parts of Australia through to five continents. The Round the World and Circle Pacific fares offer a range of affordable and attractive travel options to Australian travellers with the convenience of combining travel to the USA, Europe and the Orient into one trip," Subhas Menon, Singapore Airlines' Regional Vice President, said in a statement.