What long-stay visa should I apply for in Thailand after a short visa overstay and with intentions to study Thai?

I am posting in this group hoping for some guidance regarding a previous brief visa overstay in Thailand and my intention to return this year under the correct long-stay visa category. Hopefully the DTV soft power visa Thai language model.

I have had a close personal connection to Thailand since 2010, when I met my late wife of 11 years, Saifon. Over many years I travelled regularly between the United Kingdom and Thailand to spend time with her and her family. Saifon also lived here with me in the UK for seven years, where we built a business and a home together with our two dogs, Lucky and Harry.

After Saifon returned back to stay in Thailand around 4 years ago with lucky and harry who we flew over to be with her. We purchased land and built our home on Koh Larn Island near her family. This property has since been signed over to Saifons mother after her passing. We had just started the process of adding my name to the ownership deeds but saifon became to ill to travel to the city hall building after our first visit to begin the process. Saifons mother has told me we can still add my name to the deeds but I need to be in the country to do so.

Due to work commitments in the UK, I continued travelling back and forth on just tourist visas with extensions with a few visa runs to Cambodia as was allowed at the time and therefore I did not previously apply for a long-stay visa because it wasn’t necessary.

Sadly, Saifon was diagnosed with stage four lung cancer in April and passed away in October 2025. During that period I was caring for her, I unfortunately overstayed my permitted stay by approximately one or two days due to the immigration office being closed over the weekend and national holiday on the Monday when I was extending for a further 30 days. I was still granted the extension minus the few days I overstayed. This was entirely unintentional and occurred during an extremely distressing time. I complied with all required procedures at the time.

I now wish to return to Thailand for a longer period in order to:

• Maintain close ties with my late wife’s family

• Help care for our two dogs, who are currently being looked after by my mother-in-law

• Spend time managing matters relating to our property in Koh Larn

• Enrol in a recognised Thai language school to improve my Thai speaking ability

I believe I meet the financial requirements for the Destination Thailand Visa (DTV) and would like to enrol in a 12 month rolling program in a Thai language school. I would be grateful for any advise on whether this would be the most appropriate visa category in my circumstances, or whether another long-stay visa would be more suitable.

Additionally, I would be very grateful if anyone could advise:

• Whether my previous short overstay may affect my ability to apply for a long-stay visa.

• The correct department or email address to which I should direct this enquiry.

Thank you very much