I'm aware of the rules in Thailand about bringing your own vehicle into the country. Is it the same situation for Vietnam, Laos and Cambodia as well? Are any of these completely no-go, or is it the mandatory guide thing, or............?
Cheers.

IIRC Laos is possible, Cambodia is tricky, Vietnam is almost impossible. There are some exceptions for organized tours from e.g. Thailand, but in general it's not particularly feasible

Much easier to buy a locally plated bike in Vietnam, which should let you get across SEA borders pretty easily. For transit on a RTW trip - yeah, transit through the rest of SEA, then while your bike is in a container, fly back to Vietnam for a few weeks.

Thanks AnTyx. The plan is to come in from China on a euro plated bike. I was hoping Vietnam was possible, but if that is the least viable option, then Lao it is.

FWIW, Laos is a great place to visit! Not so industrialized as Vietnam, but still lots of amazing nature, history, great people, and the legacy of French colonialism that means the coffee and the baked goods are excellent.

Laos / Cambodia should be pretty straight forward. Vietnam is a no go at the moment unfortunately. Thailand is getting harder and harder to get in without a costly guide but still seem possible.

It's maddening how Thailand and Vietnam are managing overlanders. There's no good reasons to put so much hardship in visiting their country on our own vehicules. I just... Don't understand why. I'm planning a RTW trip in 2022 and praying some sense will get to them by then. Both countries are amazing to visit on 2 wheels.

ffs Pakistan is easier than both of them.... Boggles my mind.

Yes, nothing is straightforward! I rode through Thailand and Lao on my own euro plated bike back in 2012. No problems then, no restrictions. Things may be different in a year; who knows? Here's hoping!
Just to promote my other thread: looking for riders to join me through China/Tibet to Lao and Thailand next year around September (Covid permitting).

Antyx is spot on above here. Laos is easy to get into, at least coming from China. Coming from Thailand is a bit more difficult, but at least 2 bordercrossings is/was open for motorbikes. Cambodia can be a bit tricky, especially coming from Laos, actually almost impossible. From Thailand there are better chances. Also - it was some positive reports ftom travellers getting into Cambo before the. Covidmadness took the world by surprise.
Vietnam almost impossible unless you have a costly guide and tour organised.
Thailand - kept on changing their practise of the rules about foreign vehicles into their country. From Myanmar both possible bordercrossings kept the rule about guides and permits, from Laos in general it was difficult. From Cambodia also in general difficult, one bordercrossing usually less strict about guide and permit. From Malaysia - some bordercrossings fine, some others were strict about guide and permits.

But this was before Covid set in. Who knows what its gonna be like post Covid....?

And to repeat Antyx again - Laos is amazing. Its worth spending some time there. I had an amazing trip revisiting Laos for 24 days in January-February this year just before the world went into the lockdown. Could easily have spent 2-3 as much time there....

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In the end everything will be fine. If its not fine its not the end....

No, a VN plated bike wont get you very far in SEA. Loaos and Cambodia and that is it. You will be prohibited entry into Thailand which of course then stops you from heading down the peninsula.