Vietnam, Laos, Cambodia -- visas and border crossings

[permanent_transient]

Hi folks, I'm planning a ~3 week tour of SEA for April 2024 starting in Vietnam. I'd appreciate any advice for crossing Vietnam/Laos/Cambodia borders via motorbike. Some background:

Me: US citizen with visa exemption for Vietnam thru Nov '24. No other active visas.
My riding buddy: Vietnam citizen. No visa required for ASEAN friends.
My bike: Yamaha WR155R registered in Vietnam in my buddy's name.
My buddy's bike: Kawasaki Versys X-300 registered in Vietnam in his name.

Basic questions:

1) Is it feasible to cross Vietnam-Laos and Vietnam-Cambodia borders with our VN-plated bikes registered in his name? So far, I've read that it's tough to get a Thai bike into Laos but haven't found much regarding Viet bikes... seems Cambodia doesn't care at all but I could be wrong.

2) What type of Laos and Cambodia visas should I get? I understand the Laos eVisa does not work for any Lao-Viet land border while the Cambodia eVisa allows land entry only through the Bavet (Svay Rieng) crossing. Is visa on arrival or visa at the embassy preferable for Laos? Is the eVisa for the Bavet crossing the best option for Cambodia?

3) What are the best border crossings? I'm interested in your opinion whether it's due to ease of crossing or great roads on the other side.

Cheers!

-D.T. Leitner

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For those interested in the (vague and fluid) itinerary at this stage:
My buddy is from Soc Trang in the delta. We've discussed meeting in the south and taking the bikes to Hanoi via the Reunification Express with possible stop-offs for sightseeing and riding near Hue. More likely, he will get the bikes to Hanoi by train and meet me there. I'll get any visas that aren't eVisa or VOA there. We will spend some time in the scenic north (Ha Giang loop and the like), then head south toward the delta. If possible, we will cross into Laos at some point. We considered heading for the single Laos-Cambodia border crossing to make a big loop back to Vietnam near Soc Trang but this seems like it would skip the best Viet highlands riding in favor of the most developed sections of Laos. Hard pass. Once back in the delta, we'll make another loop out into Cambodia, then back home. The idea is to make the trip flexible. Minimize appointments and deadlines, maximize spontaneous detours.