Re: To move before Dec 31st or not?
 

Your passports will show that you traveled at the same time to the same places; not concrete but decent circumstantial evidence to get you started.
The paperwork for marriage is pretty tough in Portugal too, for foreigners. It took us months to gather everything required.
You'll likely need paper from Mongolia for it.
Really, find a PT immigration lawyer and consul by phone or email; but the important thing is to get your feet onto Portuguese ground and your signature onto a residence declaration before dec 31.
Maybe it will still be possible for you after that.
Maybe not.
I have no idea what a Mongolian person needs to get into Europe, if she can come in on a tourist visa then do that.

Re: To move before Dec 31st or not?
 

Would the UK be out of the question?

Re: To move before Dec 31st or not?
 

the UK is probably the worst place; it's a hostile environment....applying for a tourist visa for the purpose of a marriage? The registrar is required to enquire into immigration status, so you'd need a fiancé visa, which requires years of paperwork.
Weekend in Vegas?

Re: To move before Dec 31st or not?
 

None of which applies, as far as I can tell, if you are clear that you are not intending to remain in the UK and you apply for the correct visa.

Which is why I suggested it. It would also, potentially, allow the OP to demonstrate a) that this relationship began prior to the end of the Brexit Transition Period and b) that the couple are committed to it, matters which appear to be difficult for the OP to prove by other means.

Even if the request for the visa were to be declined (any particular reason why it would be?), there would be the fact of the application to be taken into consideration where applicable at a later date.

Depends on a number of other factors of course but I thought I'd mention it just in case it hasn't yet occurred to him. I haven't looked at how he could sequence things to best advantage if it were to be a runner - he's got a fair bit on his plate obviously what with all the constraints already in place.

Re: To move before Dec 31st or not?
 

the problem is proving:

• you’re not planning to stay or settle in the UK after your marriage or civil partnership

The Home Office is horrible to deal with and very much a moving target. If the OP want so go this way I would very much advise using an experience UK immigration lawyer. I thought I wasn't stupid, but it's now very difficult to get through the process of complying with the (unpublished) rules. We moved back to Brazil as we were sick of dealing with them.

eta

re-reading the OP's original post, their principal assets are in probate in the UK. They would have to provide that their ties to Vietnam were greater than that. Seriously, it's a nightmare.

Re: To move before Dec 31st or not?
 

Thanks for all your suggestions.

It’s actually quite difficult for Mongolian citizens to get even tourist visas to developed countries (Schengen, UK, USA). My ex-wife was Mongolian and we married in England in 2011. It was a nightmare to get her a fiancée visa but we had an immigration specialist and we finally managed it (after a rejection and then a successful appeal). It took quite a few months but, after she arrived, the rest was easy.

I suspect getting her even a tourist visa for Portugal could be tricky before the end of the year. I think you’re expected to apply from your country of residence, which is Mongolia, but we can’t return. So we’re stuck in Vietnam unless the Portugal consulate could issue a visa in Saigon. That seems like a long shot but we could try.

Re: To move before Dec 31st or not?
 

What about the British Consulate, don't they do weddings?

Re: To move before Dec 31st or not?
 

Portuguese representation in Vietnam is in Hanoi, not Saigon. Go and speak to them.

https://embassies.info/PortugueseCon...mission%20(HOM).

Re: To move before Dec 31st or not?
 

I wrote to the Portugese consulate in Vietnam.The person wrote back and said Mongolians can’t get tourist visas but could apply for a D7 visa in the Portugese embassy in Bangkok. I’m not sure if we can get to Thailand in the current situation. It also seems like the pandemic could get worse before it gets better due to the winter flu season coming.

I’m not sure if UK embassies do marriages but I could look into it. There’s quite a big UK embassy in Saigon. I’ve been there before.

Re: To move before Dec 31st or not?
 

:confused: The rules are all published and set out in the guidance?

Re: To move before Dec 31st or not?
 

That's how things look, but if you check with non EU, non white people who try to emigrate, you'll find that actual practice does not often follow published rules as you'd expect.
Immigration is tricky, full of pitfalls.
Immigration officers in most countries are tasked with keeping people out. That's their mission.
Don't DIY an Asian immigration application. That's like doing surgery on yourself.

Re: To move before Dec 31st or not?
 

So true!

When I applied for a UK fiancée visa for my Mongolian fiancée in 2010, the application was perfect but the UK embassy in Beijing rejected it immediately for laughable, bogus reasons. All the rejection reasons contradicted their own guidelines. Luckily, I had a visa lawyer (or paralegal) help me prepare the application then prepare an appeal. We were prepared to go to an appeal court, if necessary. Very quickly after we appealed, the embassy reversed their decision and issued the visa. Basically, they said, “you were right, we were wrong.”

if I hadn’t hired a specialist, I’d have been clueless how to proceed after the rejection. My conclusion at that time, was the same as “liveaboard”’s. They reject non-EU applicants routinely to keep the immigration numbers down (it’s politics, folks). They hope you’ll give up after rejection and probably many do. The few that persist usually with a lawyer’s help, get approved, providing their application is flawless. It’s a war of attrition.

Re: To move before Dec 31st or not?
 

However meticulous you are at complying with the requirements on the website, they will find something to put the application on hold; not an outright rejection. For us it was the intractable problem of the basic language test requirement having minimum speaking/listening scores. At the time there were listening/reading and writing/speaking exams, only one of which was available in Brazil. I was transferring to a job in my company's London office, with a job offer of multiples of the minimum; the letter of a job offer was all that was required, according to the website. Then they came back wanting Brazilian payslips and bank statements (online banking and a bank strike made going to a stationers and having a bank authentication stamp made becomes very tempting). You lose months for each iteration. So, a lawyer for a family reunion visa to got to the UK for 6 months to take the language test (because you just know you wouldn't get in as a tourist with a visa application on hold) then back to Brazil for round 3 when there were 6 months of UK bank statements, again with a lawyer to pay.

Sorry, going off topic!