The planned transfer of U.S. Marine Corps personnel from Okinawa Prefecture to the U.S. Pacific territory of Guam may start as early as October 2024 and be completed within 18 months, a marine spokesman has said.

The current plan will relocate approximately 5,000 marines, of whom about 1,700 will be permanently based on Guam and the remainder rotated every half year, according to Tina Rose Muna Barnes, speaker of the island’s legislature who was earlier briefed by a representative of Marine Corps Activity Guam. About 19,000 U.S. Marines are based in Okinawa.

The United States had previously said about 4,000 marines would be moved from Okinawa to Guam.

The planned transfer is based on a 2006 Japan-U.S. agreement on the realignment of U.S. forces. A new marine base is being built near Andersen Air Force Base on northern Guam, to be completed by 2026.

The base will be named Camp Blaz, after Marine Brig. Gen. Vicente “Ben” Blaz, a Guam native who after his military service went on to serve as Guam’s representative in the U.S. House of Representatives. He died in 2014.

1st Lt. Brett Lazaroff, a communications officer in Marine Corps Activity Guam, said recently by email that the transfer of the 3rd Marine Expeditionary Force is expected to begin during the first half of the fiscal year that begins in October 2024.

Approximately 2,400 dependents will be accompanying the 5,000 marines. Guam currently hosts around 7,800 U.S. service members.

A number of infrastructure projects, including the construction of roads and medical facilities, are being undertaken to cope with the expected surge in the island’s population. But concerns have mounted over delays in such projects due to a lack of skilled labor.

The environmental impact of the construction and the work’s potential influence on the island’s cultural resources, such as prehistoric features, have also spurred concern among locals.

The Spirits of the People of Guam, a local nonprofit group, says the marines’ relocation raises concerns about the impact on the island’s public safety, social services and public utilities.

“As with any construction projects in Guam, there are always challenges to overcome and concerns that need to be addressed. Some of these are a shortage of skilled labor on Guam, and environmental and cultural concerns,” Lazaroff said.

He stressed, however, that the U.S. Marine Corps is trying to mitigate concerns through transparency, dialogue and partnerships with local government agencies while balancing the need to build a military base.

Guam Gov. Lou Leon Guerrero says her administration will proceed responsibly with what she says is an expensive military buildup for the island that comes with an $8.7 billion price tag, including an up to $3.1 billion contribution from the Japanese government.

“With the military buildup and the economic influx it will bring, our administration is determined to see that it be done responsibly and at a pace that will benefit and respect our local people, culture and environment,” the governor said in an address in April.

The force realignment plan revised by Japan and the United States in 2012 stipulates that approximately 9,000 U.S. Marines in Okinawa will be relocated outside Japan, to such places as Guam and Hawaii. The plan also includes the relocation of a U.S. Marine air base to a new site within Okinawa.

The planned base relocation to the Henoko coastal area of Nago, which involves landfill work, has run into stiff opposition from locals and environmental groups, with the government of Prime Minister Shinzo Abe pushing ahead with land reclamation work nonetheless. The two countries have agreed to decouple the U.S. Marines’ Guam relocation from progress in the base relocation on Okinawa and start relocating Okinawa-based marines to the U.S. territory in the first half of the 2020s.

But Chief Cabinet Secretary Yoshihide Suga acknowledged in October that the two projects are “consequently linked,” suggesting that the United States would not proceed with the Guam relocation unless the base relocation happens in Okinawa