Ships, submarines and aircraft from more than 22 nations are taking part.
Australia is sending two frigates and a submarine.
But there's one notable absence - China.
Presenter: Brendan Trembath
Speaker: Admiral Jonathan Greenert, US chief of naval operations
BRENDAN TREMBATH: The world's largest maritime exercise starts this week in and around the Hawaiian Islands.
Admiral Jonathan Greenert is the US chief of naval operations.
JONATHAN GREENERT: We've been doing RIMPAC (Rim of the Pacific Exercise) for over 40 years now. This year is different because it's bigger. It's wider ranging if you will.
You may know we had a nice event last night and a successful test for our missile defence system, off of Kaua'i; so that's a good way to kick things off.
BRENDAN TREMBATH: He spoke at a Pentagon briefing.
Japan, South Korea and Canada are taking part as usual. Australia is too.
The Royal Australian Navy is sending the frigates HMAS Perth, HMAS Darwin and the submarine HMAS Farncomb. They'll be part of a large fleet.
JONATHAN GREENERT: From South America, North America, NATO (North Atlantic Treaty Organization), the Russians.
BRENDAN TREMBATH: Yes the Russians. He probably never thought that would happen when he graduated from the US Naval Academy in 1975 and served on submarines.
One of them was the tiny nuclear-powered research submarine NR-1, which was used on various covert missions during the Cold War.
US Russia relations have thawed since then.
And it's not out of the question for China to join the RIMPAC fleet.
JONATHAN GREENERT: You can be sure that would be an endeavour and I hope some time in the future we can, it's a, the details of which I don't have but clearly the more the better in an exercise such as RIMPAC.
BRENDAN TREMBATH: This year will also see the first use of biofuels. The US Navy will evaluate how well they perform at sea and in the air.
US corn growers, who are big supporters of the biofuels industry, will be pleased. But bio fuels are more expensive.
Admiral Greenert says it's still worthwhile investigating alternatives to oil.
JONATHAN GREENERT: Just during my tenure we've had swings in the price of oil of $20, $20 up, $20 down. That's $30 million in our budget for every dollar, so $600 million swing up, $600 swing down. That complicates the budget to say the least.
So some of our endeavour is to look for alternate fuels and in my world what I track very closely in energy is most efficient use of it, at sea and ashore from our peers to our facilities and as we bring new ships in, as I bring forward my requirements that I'm thinking fuel, because, I gotta tell you folks, it's clearly to me a factor in security.
BRENDAN TREMBATH: Admiral Jonathan Greenert also has to think about the long-term impact of a changing climate. While RIMPAC takes place in the warm waters of Hawaii, the US Navy is increasing its operations in the Arctic, as higher temperatures melt the sea ice.
JONATHAN GREENERT: We're working with the Canadians and with the Norwegian Navy. We've been doing a series of exercises in the Arctic.
So the concept of operations, for Arctic operations we've been developing for a number of years; five, six years now.
BRENDAN TREMBATH: He says they're looking at how ships, crews and equipment work in the far north.