The first group of about 200 US Marines have arrived in Darwin today.
About 1200 Marines are coming as part of the ninth Marine Rotational Force - Darwin (MRF-D).
Defence Minister Linda Reynolds said their arrival was the result of extensive planning and coordination between both nations to address challenges posed by COVID-19.
"MRF-D is an important initiative that deepens interoperability between the Australian Defence Force and the US military," Minister Reynolds said.
"Australia's Alliance with the United States is our most important Defence relationship. It sends a clear signal about our commitment to the security and stability of our region.
"The fact that we were able to modify MRF-D and mitigate risks associated with COVID-19 to allow it to proceed is a strong testament of the resilience of our Alliance."
All Marines will be quarantined for 14 days at Defence facilities in the Darwin area, following biosecurity screening and COVID-19 testing on arrival.
The Marines will be tested again for COVID-19 before exiting quarantine.
These arrangements have been established after close consultation with the NT Government, she said.
The US Marines will train with ADF personnel at various Defence training facilities around the greater Darwin area, including Mount Bundey and Kangaroo Flats.
MRF-D will grow to 1200 personnel over the next eight weeks, and will train through to September.
The rotation will finish with the signature MRF-D/ADF bilateral high-end warfighting activity, Exercise Koolendong. The Marines will then redeploy back to Japan and the United States.
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