It's quite easy. I am going around-the-world with OneWorld next year.
Economy is $A2500 approximately.
From Sydney, I am going to Hong Kong, then to Tokyo and then back to Hong Kong. This is using two of the four flight segments I can use.
From Hong Kong, I am going to London, then Amsterdam, Dublin, Berlin, London. This uses all of my four flight segments. The restriction I came across in Asia is that you can't use OneWorld to fly Hong Kong to Ho Chi Minh City (Saigon) on Cathay Pacific, even though they fly there. I was told I'd have to go to Bangkok and then to Ho Chi Minh City.
In North America (which includes Central America and the Caribbean) you have six segments. Only one trans-continental USA to use, and there is a special restriction regarding Hawaii.
Therefore, I am going to Antigua in the Caribbean, San Juan, New York, Orlando, San Francisco, Dallas and then to Vancouver.
As I am living in Dublin for 10 months, then Vancouver for 12 months, I won't use my return Los Angeles to Sydney flight (I'd have to pay to get to LA
anyway, as I'd be out of segments).
That is the 4 continents journey and all for $A2500. Business Class is $A9100. It's cheaper on Star Alliance, but I imagine that's related to product.
The thing you need to do is visit the OneWorld alliance carrier web sites. You have to be able to take a OneWorld carrier between two points, hence why I am going from London to Antigua on BA
, Antigua to San Juan on American Eagle, then San Juan to New York on American. If the airlines don't fly between two points, you can't fly on the ticket between those points.
Additionally, the tickets last 12 months with no extensions, and nor can you upgrade for any segment of the journey by paying extra. Any unused segments are lost and non-refundable.
Finally, you earn points as normal on all your flights - no half points or any of that like you usually would with discount tickets.
Calling your OneWorld home carrier and telling them the itinerary you want will be easiest, but do the research on your cities and what not beforehand. Also be careful - I asked a travel agent and they told me I couldn't do some of the things I wanted to do, because they were reading their screens incorrectly.
Hope this helps!