How can I apply for a Non Immigrant O visa at the Immigration office in Hua Hin without using an agent?

Go to Immigration , help desk and hopefully be guided. Best of luck

You go to the biggest immigration office in your area and they will instruct you on what you need to bring and what forms need to be filled out and even check to make sure the forms are done correctly. many people use an agent because this process can take 1 to 2 days.

Can anyone advise me please how to apply for a Non Immigrant O visa at the Immigration office in Hua Hin without the help of an agent?

*** No, it is not possible without the help of an agent, because you need an existing Thai bank account for this, which you do not have and which you cannot get opened on a touristic entry.

*** in Bangkok and Pattaya there are a handful of agents who can do this for you. Their price starts up from 60,000 Thai Baht (almost 2000 US Dollar)

*** apply for the 90-days Non-Imm-O Visa outside of Thailand, pay a fee of 80 Dollar. In Thailand, open the bank account, put 800,000 THB into your Thai bank account and apply for the 1-year extension, the fee is 1900.- Thai Baht

Go to immigration and ask them what they need . They will tell all the paper work you need and fill and apply easy

Done at a Thai Embassy or Consulate outside of Thailand

There should be a pinned post on this step 1 etc ?

It’s applied for outside of Thailand. Best thing is to visit the e-visa website, they have the list of requirements. Very straightforward. You don’t have to apply from your home country, just from outside Thailand. And no you don’t need a Thai bank account to apply for a non-o.

You have to apply outside Thailand !!!!

Unless you have a Thai bank account with the required funds

What type of entry are you currently on? And do you currently have a Thai bank account? If you don't have a bank account you won't be able to open one on a tourist entry stamp so you would need to leave Thailand to a nearby country, apply for the 90 day Non-O at the consulate relevant to where you travel to, return and open the bank account and deposit the required funds for an extension of stay depending on whichever Non-O you have. The funds need to be in the account for 2 months before you can apply for the extension so that's the priority on your return

Non O visa is usually applied for outside of thailand, and then extended once you arrive

First you need a Thai bank account on your name with 800k THB on it.

Non O based on what?