What are the best options for a 20-year-old seeking a one-year visa in Thailand?

For what??

If you're on a Visa On Arrival you have to leave after 15 days - no extensions. I actually think you're on a free entry stamp

you don't have a "visa-on-arrival". You are here on a visa exempt entry and received a 30-days stay permit

I think you have a lot of research to do rather than asking for otger Favebook users to supply you with solutions and "contacts".

If you want to so it the "not-so-legal' way, fins the nearest Visa Agent and go inside...

Otherwise, my advice would be to return to your home country and obtain a METV (if available to you) and come back to Thailand with that, at least. That, worked to it's maximum, will give you nine months of stay in Thailand. Id then leave for a week or so (Nice holiday to Malaysia or the like) and then come back with a Tourist Visa which will give you 30 days (currently but by then potentially 6o days) rhen extend that at the local immigration office (at a cost of 1900THB currently) for a further 30 days.

That's the best part of a year covered.

Ask your daddy for a lot of money and invest it in Thailand.

Got Yer first taste-O-Honey?

You need a one year visa, so you have a reason to stay in Thailand for a year? Then you are the only person who can say which visa you need.

Have you ever been in Thailand longer than a couple of weeks holiday ?

If not you may find out that, everyday life is much different from holiday life.

How do you want to finance the stay in Thailand.

It will be difficult to get a workpermit, and on touristvisas work is STRICTLY forbidden, even voluntering without a salary, and with you age in mind, the most jobs you could get is reserved for Thai people only.

ED visa is only an option, if you really want to study, fulltime you will have to attend classes, and may be tested by immigration that you learn some thing.

What you need and what you can get is often not the same. You could applied for a six months multiple entries tourist visa at home before you left and stayed for up to nine months in Thailand. This is only available from the embassy/consulate of your permanent residence.

I guess you’re not on a 15 days visa on arrival, but a 30 days visa exemption. This can be extended with additional 30 days at your local immigration. You should be able to do several border runs to get a new exemption, but you can’t expect to do a long term stay with this. There’s some options regarding ED visa for studying Thai as an example and also Muy thai visa if this can be an option for you. You’ll need to investigate this further.

If you have enough cash, get an Elite Visa. If you don't want to spend that much money or think about a one year stay in Thailand only, i recommend the METV and some border-runs or Visa-runs. 3rd option is the ED visa to study Muay Thai boxing or anything else, but you need to attend the classes.

Ed visa

Are you willing to study at a school? That's likely to be your only option at your age. A multi entry tourist visa can give you close to 9 months with a couple of border bounces