Manly, Australia, has embraced its feminine side.

The coastal suburb of Sydney may have a testosterone-heavy name. But the popular surfing destination signed on Thursday as Huntington Beach's new — if unofficial — sister city.

Representatives from Huntington and Manly signed an official memorandum of understanding at a ceremony during the first Australian Open of Surfing, a weeklong event taking place through Sunday at Manly.

Chris Cole, the specific events coordinator for Huntington's Community Service Department, made the flight to represent Surf City.

"Huntington Beach is 'Surf City USA,' and Manly is unquestionably 'Surf City Manly Australia,' so it is ideal that we become sister cities," Manly Mayor Jean Hay said in a release. "The establishment of a sister city relationship serves to promote friendship, cooperation and cultural exchange between the two communities and act as a core for community exchange and contact between ordinary citizens."

Huntington Beach City Councilman Joe Carchio met Hay and other Manly officials during last year's U.S. Open of Surfing. As the group toured Huntington, both sides hit upon the idea of becoming sister cities, Carchio said.

Huntington has one official sister city in Anjo, Japan, and the two cities have hosted student and adult exchanges for the last three decades.

However, Manly's sister-city relationship with Huntington will be on an informal basis, meaning that the cities will not be registered under Sister Cities International and no staff time or money will be spent on programs, according to city spokeswoman Laurie Frymire.

"I don't know if there's anything planned other than getting the MOU signed," she said.

The document declares that Manly and Huntington "shall maintain regular contact with a view to facilitate future cooperation on matters of common interest."

Carchio said he wasn't sure to what extent the cities will collaborate in the future, but said lifeguard exchanges are one possibility. The MOU, he said, largely symbolized the cities' status as havens for surf culture.

"I think it's going to be a great relationship," Carchio said.

michael.miller@latimes.com

Twitter: @MichaelMillerHB