Scepticism is entirely appropriate if you've ever done much backend heavy vibe coding. It's how I(/we) ended up building ways for a GPT to be more helpful for such tasks and thus why I am interested in small real world useful apps with a knows-the-field collaborator as that's a good way to stress test the approach.

I have built an RTW itinerary which I believe ends up as a DONE3 OneWorld Explorer, I get this message on the 'Choose Cities' page

Estimated Segments: 13 (max 16), Stopovers: 12 (min 2, max 15), Miles: 34529, (max 34000) , Itinerary Status: Valid

and when I move on to the 'Select Flights' page I end up with 15 Segments and I successfully select all the flights. The Miles: 34529, (max 34000) part of the message doesn't seem to be an issue.

However when I try to add in an extra leg as in HKG-BKK-DOH becomes HKG-KUL-SIN-DOH on the 'Choose Cities' page I get

Estimated Segments: 14 (max 16), Stopovers: 13 (min 2, max 15), Miles: 34703, (max 34000) , Itinerary Status: Valid

and when I move on to the 'Select Flights' page red banners keep popping up saying 'Error Your itinerary exceeds the 34,000 mile limit on a Business or First class booking. To finalise your itinerary, please reduce the length of your trip'. I can still select flights and I work my way through it all but I never get to the end, a 'Review Flights' button.

I am trying to turn this
OSL-LHR-MAD-LAX-JFK-AUS-MIA-SLC-DFW-JFK-HND-HKG-BKK-DOH-LHR-OSL

into this
OSL-LHR-MAD-LAX-JFK-AUS-MIA-SLC-DFW-JFK-HND-HKG-KUL-SIN-DOH-LHR-OSL

I'm now getting message to say that there are no flights from OSL-MAD which I am taking as an indication to take a break and start again - probably tomorrow!!

Have you checked there are OW non stop D fare bucket flights between your airports on the day you want?
Tokyo NRT HND can be an issue with some itineraries.
KUL SIN is a very short flight [or train ride]
A Oneworld explorer *ONE* defaulting ~ error to the 34,000 Global explorer is common.
The online tool is thinking you are booking a 34,000 mile Global Explorer. Not a *ONE*
--> https://www.oneworld.com/round-the-world

A map from the Great Circle Mapper - Great Circle Mapper

A map from the Great Circle Mapper - Great Circle Mapper

If you are just getting the no flight available then I think that message does mean the tool can't find a flight. The other messages do mean there is a routing error in my experience. Please post if you find out differently.

Do you want to book using the tool? If so it will have to show flight availability.

If you are just checking routing and possible costs (which is what I use the tool for) then just adjust dates until your routing prices. Then you know the route is valid and the approximate price.
Even if you get a route that prices whoever you book with may show different availability and different price but you should be close enough to get started booking for the dates you want.

Also I find it helpful to save itineraries that do price to fall back to.

And taking a break often magically makes things start working.

I'm using the OW RTW online tool for to see if it'll route me a trip in June 2026 I want which includes a flight between Quito (UIO) and Oslo (OSL) or vice versa. Although Iberia fly direct between UIO and MAD, the RTW only gives me two-stop options on American Airlines between Quito and Miami then Miami to Madrid followed by an Iberia flight between Madrid and Oslo.

I adjusted the dates a bit, but the tool never gives me a one-stop Iberia UIO-MAD-OSL. Is that a bug? I'm not an expert with OW. Also, it never gives a two-stop via LHR with BA, instead of MAD, with AA/IB - not that I would want that route.

Taking a break was the magic sauce, admittedly I have removed all but one of the US domestic legs so the overall mileage is reduced but that 'allows' me to work on the HKG-BKK-DOH or HKG-XXX-XXX-DOH portion of my plan - magically OSL-MAD has flights again.

Hopefully I can add the US domestic legs back in once I get the far east portion sorted out, although I may try approaching a travel agent with a valid 15 segment trip and ask them for any suggestions to add a convenient 16th segment.

I believe I have discovered why certain itineraries, that involve two departures/arrivals from/to Europe/Middle East, are failing – it is because there is a Zombie rule still lurking in the tool. It should have died NINE years ago but is still there.

Bear with me while I take you through my reasoning – it gets a bit complicated.

______________________________________

The current rule is:

4(e) Only one intercontinental departure and one intercontinental arrival permitted in each continent except as follows:

1. Two permitted in North America.

2. Two permitted in Asia.

3. Two permitted in Europe/Middle East for travel to/from/via Africa. If travel is to/from Europe in both directions, itinerary may not include Mauritius/South Africa.

Exception 3. Refers to Europe. This is defined in Rule 0 (zero), as follows:These zones are only ever mentioned in the above Exception 3 to Rule 4(e), and in fact only the Europe Zone is referred to.
______________________________________

Stimulated by a post by wandering_fred in another thread, I have been playing around in the tool with various ex-South Africa itineraries. This is one I tried to price up:

CPT-LHR-HKG-MNL-HKG-PER-HKG-KTI-HKG-YYZ-LGA-ATL-LHR-AMM-CAI-MCT-ZNZ

This itinerary starts with an Africa-Europe Zone flight (CPT-LHR) and ends with a Middle East Zone-Africa flight (MCT-ZNZ). So it complies with Exception 3, and therefore South Africa can be in the itinerary. But it wouldn’t price, I was getting the usual “Exceeds 34,000 miles” error. After double, and then triple-checking every flight, I was stumped. I went back to the first screen on the tool and clicked on the “Fare Eligibility” button (at the top right of the “Build Your Itinerary” screen). The Oneworld Explorer showed as Invalid. It was the LHR-AMM flight causing the problem. The error message is:The wording of the first sentence was familiar to me. It is the wording used in a version of Rule 4(e) that was replaced years ago. The Rule back then (prior to May 2016!) was much more complicated and had the words “Travel may not include any flown or surface sector between Europe and Middle East”. (Yes, I have a copy of that old rule sheet.)

So my conclusion is that there is a Zombie rule lurking in the on-line tool! To verify it I made two changes to my itinerary

1. I changed ATL-LHR-AMM to ATL-DOH-AMM. This itinerary priced up OK. To me this means there is no problem with South Africa being included in my Africa-Europe Zone…Middle East Zone-Africa itinerary,
2. I set the itinerary back to ATL-LHR-AMM and I changed the starting point to NBO (so the first segment is now NBO-LHR). The same error was flagged on the LHR-AMM segment, but now neither South Africa nor Mauritius is in the itinerary, so the “error” has nothing to with the current Exception 3 to Rule 4(e).

______________________________________

So I am convinced I know what the bug is. But how to report it to Oneworld? There used to be a ‘feedback’ facility on the website, but that is long gone (IIRC they were getting requests to fault-check people’s itineraries, rather than flagging issues/making suggestions regarding the tool itself).

Does anyone have a contact within Oneworld?

Thoughts/comments/feedback welcomed 😊

I'm still playing around with Oneworld Explorer itineraries starting in Africa
Currently experimenting with itineraries beginning with Oman Air starting from Zanzibar (which is not far from where I am at present - the Kenya coast, north of Mombasa)

So, first flights are ZNZ-xMCT-MNL, both flights operated by Oman Air
But the tool doesn't like it; the message is
(that's a direct copy, complete with typing errors)

Any ideas anybody?

I tried a quick RTW ex-ZNZ and got a different, even more baffling error.

WY flies ZNZ-MCT only on Sunday, Wednesday and Friday (according to EF)

I tried those days.

So weird. I swapped ZNZ for DAR, same issue. Then tried ex-CAI and it correctly showed me WY406 as expected.

I've got my fully priced DONE5 up on my screen right now

First flight is WY708 ZNZ-MCT on October 17th

Yep. ZNZ-MCT actually operates Monday, Tuesday, Wednesday and Friday in August so selecting the right date and it completed. Most unhelpful error though.

Does the tool just sit and spin while loading for anyone else today? - Looks like they pushed a new change overnight and it broke things :/

It was working "OK" this am. Hope it is for you.