The first detachment of about 1200 United States Marines will touch down in Darwin in a few weeks.
Strict testing requirements are being in place to make sure they don't bring coronavirus in with them.
Their arrival comes as the NT now only one active case of coronavirus with another patient cleared yesterday.
The recovered case and the remaining case contracted COVID-19 while serving overseas with the Australian Defence Force.
All 30 cases of COVID-19 diagnosed in the Northern Territory are related to international or interstate travel.
There have been no cases of community transmission in the NT.
The first group of US Marines will disembark at RAAF Base Darwin in early June, beginning the Australian component of a detailed quarantine and testing regime.
Defence Minister Linda Reynolds said the deployment demonstrates Australia's close defence relationship with the US.
"The Marine Rotational Force - Darwin exemplifies the strength of the Australia-United States Alliance and sends a clear signal about our shared commitment to regional security," Minister Reynolds said.
"I am pleased that the modified deployment will proceed this year, following careful planning and preparations undertaken by both Australia and the United States to minimise COVID-19 risks to the Northern Territory."
Each Marine will be screened four days prior to departure.
They will then be screened and tested for COVID-19 upon arrival in Australia, before being quarantined for 14 days at specially prepared Defence facilities in the Darwin area.
Each Marine will be re-tested at the conclusion of the quarantine period.
The modified rotation will involve around 1200 Marines who will exercise exclusively at Defence training areas in the NT.
It is not known if those training areas will include Tindal RAAF Base but they have in the past.
A total of 2500 Marines arrived in 2019.
"The Marines will achieve significant training outcomes with the Australian Defence Force while rigorously adhering to the restrictions in place to safely manage COVID-19 in the Territory," Minister Reynolds said.
"This rotation has been able to proceed, with all the necessary protections related to COVID-19, because of the excellent cooperation between the United States Marine Corps, the Australian Government and the Northern Territory Government."
The Marine Rotational Force-Darwin is a US Force Posture Initiative that deepens interoperability between the ADF and US military, supports increased regional engagement with partners in the Indo-Pacific, and better positions our forces to respond to crises in the region, including humanitarian assistance and disaster response operations.