What are the new requirements for applying for the Destination Thailand Visa (DTV) and can one apply from a country other than their passport country?

What is his age?

When you get the non O after married you can only apply for 1 year extension with 45 days remaining. You then go under consideration for 1 month before the extension is granted. so this will require 2-3 months application process. That's also if he already has a bank account and can season the required fund 400K.

I work offshore on a rotation basis and ended up with retirement extension so i not miss out on income.

As NongTong Osk has mentioned, things will be much easier if you marry in Thailand but again, your husband's work rotation could cause you problems. A new policy came into force last year and now, most Amphurs will not marry you immediately. You have to take your application and other documents to them and wait whilst they check them - this can be 1 week or 2 months. However, there is a way around it - some Bangkok Amphurs offer a same day service (for a fee and normally through an agent). You will be taking various documents to a translation agency in order that they can then be legalised by the MFA. That agency will also know which Amphurs will do the same day service. I would also recommend that you let them take the translated documents to the MFA for legalisation as doing it yourself its a real pain in the ass these days. Your husband will have to get some sort of proof that he is free to marry from his country's embassy in Bangkok which normally requires a booked appointment. The translated documents then need to be legalised by the MFA which also requires an appointment................as I say, much easier to let the translation agency do everything. 14 days is enough as long as your husband books the appointment at his embassy for as soon as he arrives in Thailand.

Regarding after you are married: When you get the Non O Visa based on marriage you will then need to extend it by 12 months. You cannot do that until at least 45 days into the original visa (some Immigration Offices may vary on that). If your husband intends leaving Thailand often - that's when things can get tricky. Once you complete the application for the extension an under there is an consideration period which will be stamped in your husband's passport. This is normally 30 days during which time Immigration will visit your marital home to establish whether you both live there or not so you both need to be there. In theory the extension should be ready at the end of that 30 day period. However, some offices will not give him the extension until 30 days after his visa ends. I have just had a problem over this as I need to leave Thailand for a while. The best way to be able to decide when your husband is able to leave and when he must return is to go to your local Immigration office and tell them of your plans. They should be able to tell you when he needs to be in Thailand and when he is free to leave. If he leaves Thailand after he obtains his Non O Visa - either before you get the extension or after its been granted, he will need a re-entry permit as neither the Non O or the extension are multi entry. If he leaves without one both his Non O and his extension will be cancelled and you'll have to apply again. A single entry re-entry permit costs 1000 baht and a multi entry one costs 3800 so he will need to get the one that best suits his work rotations. I cannot stress enough how important it is for you to work out your calendar with immigration to make sure your husband will be back in the country to collect his extension.

I recommend comparing the legalisation process for both options: marrying in Thailand vs. Australia. Registering your marriage in Thailand and obtaining the Kor Ror 22 (คร. 22) is much simpler. In fact, if you hold a Thai marriage certificate, a Kor Ror 22 may not even be required for a Non-O visa extension. Conversely, if you marry in Australia, you will be required to translate and legalise both the marriage certificate and passport to obtain the Kor Ror 22, making it an essential step for his Non-O visa.

Regarding the visa, applying for a multiple-entry Non-O visa is the best path if he is 50+. It is best to avoid changing visa types frequently when traveling in and out of Thailand. Consistency and transparency are key.

He can enter on visa exempt for all those entries with no problem at all. He is not showing a pattern of trying to live here long term as a tourist. He is setting a pattern of being an actual tourist, and Thailand likes that

He can come in on a visa waiver and if he can prove he works rotation he shouldn't have any issue with immigration... He just spends time off with his fiancé in Thailand

METV

A Multiple Entry Tourist Visa (METV) would probably be best to cover these trips. It's valid for 6 months from the date of issue and every entry gets him stamped in for 60 days.

On the subject of a Non-O visa based on marriage, I'm assuming you will get married in Thailand, a number of immigration offices won't allow him to apply for that visa inside Thailand until he's been married for 3 months, you'll need to check with your local office.